Others say...

"Could be easily much better"
Installation happened to be very straightforward. Setup was tricker, but doable. The user's manual as all manuals written poorly. The worst part of it is the backup software. If you want to use it as a backup drive, beware.
Ideally, the backup shall run in the background, constantly backing up your files to the drive and you shall not be concerned about specific setup. LaCie offers a backup where you have to manually initiate it, manually select files and folders and manually select target. Or you can leave it with the default backup of entire "My Documents" directory to the external drive and still you will have to start it manually. With this software we are back in early DOS times when XCOPY command was not yet invented, let alone luxuries like incremental backup (which came as standard software with my first tape backup long time ago). No optional software upgrade is available. You may elect to buy a backup software additionally on the market (allegedly any of them will work with this drive), but most of these backup programs are using proprietary file format and that makes the backup files not accessible directly from the Explorer. Therefore, if your computer fails and you hope that your backup files will be readily available from another computer, you are wrong!
Last but not least matter is price. With the package, you will receive an offer of Advance Replacement. If your unit happen to fail, LaCie will send you a replacement before you return failed product or part, shipping paid. The cost of this offer is about $115, i.e. about 1/3 of the Amazon price! Of course, you don't have to buy it, but then you have to ship the unit/part, pay the cost of shipment and LaCie will send you replacement unit within undisclosed period of time, while you are entirely unprotected, although you did pay the money. This situation dictates practically buying this option, but the final price is radically higher than the advertised one. On top of it, LaCie will not protect your data whatsoever! If you loose a drive, you have to take care on your own for data recovery, prior to shipping it for replacement, since even if the drive happen to be repairable, LaCie will re-format it (data loss!) even if the data would be recoverable. Think twice before you go for it. It sounds like you are dealing with a proverbial used car dealer.
The standard manufacturer's warranty provides technical support. At first you will see no other options but web-based e-mail service, which if you try, you will be waiting for the TS response a week or more. Deeper in the LaCie web site guts there is a telephone number buried.
If disaster happens you will have to send back faulty unit at your cost to the manufacturer and they will attempt to repair and eventually send you back refurbished unit. Your data will be lost, since they do not attempt recovery; they will wipe out the disk.
The manufacturer offers extended warranty plan under which, they will send substitute and return label first and then you may try to recover the data, but it is available only if the extended warranty is purchased within 30 days from the unit shipment from the factory. But shipped not to YOU but to the reseller. The chances are that the unit will be shipped to you AFTER the 30-day period expired (and that happened to me)and you will not be able to purchase the extended warranty.
The Amazon-offered extended warranty service is not even near to the one offered by the manufacturer, actually it is an equivalent of the manufacturer's standard warranty (thus completely unneeded), and available only at the moment when you buy the unit. It is not so obvious, you have to scroll down and read all stories before you get to this information, therefore beware, it is easy to overlook it.
Solution? Buy second drive to your computer and a decent backup software. This way you are to be better protected than with LaCie.
As they say, the road to hell is paved with good intentions. Undoubtedly both Amazon and LaCie wanted to provide us with a superior product, but in it's stead we are getting standard product with less than standard service and inferior software.
Don't buy it! Save these $300+ since it is not worthy.

"Don't be fooled...."
While this product advertises a 1 gigabit network card, it actually has a throughput equivalent to a 100 megabit network card, which was the standard about ten years ago. I spoke with customer service and they said 6 to 12 megabytes per second is the normal write speed. Your internal hard drive is probably running at 400 megabytes per second.

Why worry? Because when I use it for backup, it is not unusual for me to see an elapsed time of 4 or 5 HOURS. I have a 1 gigabit network because I need it. But this drive does not operate at that speed.

And not only that, it seems to have a problem with writing the date created for the new file, and instead uses the date modified for the old file in both the date modified and date created. Again I talked to customer service for the limit of my patience and got nowhere. My usual backup software was rewriting every file every time because of this. I did find something different to use, but should not have had to do this.

"Not for Mac"
This is a warning for Mac users. Though I've seen that there is a review from a Mac owner on this page who's not complaining about my problems.

I wanted to use the drive as backup device for my macs (leopards and tigers). Unfortunately it seems that the LaCies AFP implementation has some serious problems. One of them leads to setting the invisible attribute switched on for every transferred file. Which forces you to use some developer tool (SetFile) to switch it back. This does not happen for every app but one is rsync an for that matter every backup solution I know.

The problem seems to exist for a couple of other apps too. Google for "Lacie afp invisible". Customer support in germany confirmed the problem saying that there is no workaround.

Since I'm a developper I might come up with a patched version of rsync but thats probably not your thing. Actually its not mine either and it frankly puzzles me that such a thing went through LaCies quality assurance.

Anyways that problem is Mac only. Can't say anything about other environments.

"Pretty cool for a home media server"
I purchased this so a few people could store their music, photos, etc., in a single place. Using it with 3 Apple computers and an Airport Extreme in RAID mode, so the data is all backed up. Feel completely nerdy but it is easy to set up and use, and works as advertised. Do NOT purchase this unit unless you definitely intend to connect it to a router via ethernet, it will not connect straight to a computer as far as I can tell. They make the same thing in triple interface format for that purpose. This unit is not what I would call quiet. If your router's in a room that's not where you sleep or relax it won't make the least bit of difference. It gets hot, too. I had in an enclosed cabinet and it got hot beyond what I was comfortable with, so now it's out in the open, which considering its size and rather clunky appearance (and huge blue light) is a little funky, but again, if you're connecting it to a router somewhere out of the way, again it won't make a difference. Setting up accounts to access are via a web interface, and while fairly straightforward, I would say if you're a tech newbie this may not be great for you unless someone can help you set it up.

"Does everything I want"
I needed a drive that would serve as a backup for my most important files, and also allow me access to important files from abroad. This does both.

I originally purchased a WD World Edition, but returned it immediately after I discovered that WD places a restriction on certain file types, and also requires the use of third-party software in order to remotely control it.

The Lacie drive as compatible with FTP, AFP, and SMB, so I can access it from anywhere using an Apple or Microsoft machine. Transfer speeds are exactly what I expected: Extremely fast when accessed from my internal network, and understandably slow when pulling files from outside the network (speed when downloading from abroad will be dictated by your home's upload speed).

the RAID configuration is simple: just specify (when you setup the drive initially) that you want to run it in SAFE mode. This way you'll have roughly 732 GB of space, with an automatic backup in case of drive failure.

A few minor downsides that I can think of: 1) The drive is pretty bulky 2) It is also somewhat loud 3) If a drive fails, I think you need to get a replacement direct from Lacie, as opposed to simply going out and buying a new drive. (That might be Lacie trying to get more money out of us, not necessarily a restriction).
I highly recommend this great drive!