Others say...

"When compared to Sanyo 2700 there is no comparison"
I have 12 of these Sony batteries.
I got them without checking out the reviews.
Then I got the LaCrosse battery charger which allows you to charge at different rates and actually see how much the milliampHour is stored.
I also read the reviews and got interested in the Sanyo 2700.

Bottom Line:
If you are uninformed you will like the Sony's
I regret purchasing before becoming informed.

Take note that there are two types
Rechargable around 2700 maH
and
PreCharged around 2000 maH
The PreCharged will hold self life over a year from what I have read here.

Don't waste you time with anything besides Sanyo.

You're on your own now...at least you have been informed.

"Leaves Alkis in the DUST!"
I do a lot of instrumental music recording and performing, and I use these Sony rechargeables EXCLUSIVELY in my gear, the most power-hungry of which are my Zoom H2 Handy Portable Stereo Recorder and my GigLight Compact LED Music Stand Light. I also use them in my Canon PowerShot A720IS 8MP Digital Camera with 6x Optical Image Stabilized Zoom when going "optical" rather than "audible."

I can EASILY record two hours of music on my H2 with two of these batteries at 44.1kHz, 16-bit. I have never even come close to their running out early, and I've never had the device quit because of a lack of power. And I have recharged these MANY times for MANY gigs.

Loading my GigLight with these, I have found I can run it OVERNIGHT -- even 24 hours! -- and not drain them completely.

Plus, the batteries last between 200-400 pictures in my Canon, depending on whether I'm using a lot of flash and whether or not I leave the AF on "continuous." I'm never short of power. It's amazing.

Charge time is very reasonable, and when I use the H2, which uses only 2 batteries, I have a spare pair at the ready if I need them.

These leave Alkis in the dust! HIGHLY recommended -- and that's high praise because I'm generally NOT a Sony fan. But I am a fan of these!

"Awesome batteries! Quick charge!"
these are exactly what I was looking for. Came fast, charged up and have not needed a recharge in almost 2 weeks! Im using a Coolpix Nikon Camera!

"Pretty God but the 2700mAh would be better"
This pack is really good, the price is worthy, they works perfect, I buy this as a bundle pack with the charger, but the charger comes with a 2700mAh, so, If you care a lot duration time, notice, that using this 2500mAh with (example) a 2700mAh would be like using all batteries of 2500mAh.
I bought this because I need for my Lego Mindstorms NXT, since the official Lego battery (and charger) cost much, much more.

"Self-discharges at an alarming rate"
I bought 4 2300mAh Sony batteries in 2002 when I bought my digital camera. Those worked pretty well but after a year, they started self-discharging at an alarming rate and couldn't keep their charges longer than a few hours.

Since they worked pretty well for me at first, I decided to continue with Sony and I bought some 2500mAh batteries to replace the 2300mAh ones. Bad mistake. The newer batteries were similar to the old ones and self-discharged at crazy rates. Still, I wasn't sure if I had bought some fake Sony batteries as I didn't believe that the quality would be so bad.

So, two years ago, I happened to visit Tokyo and I bought 4 new Sony batteries and a charger there because I had read that batteries in Japan were sure to be the real deal and usually performed better. Same problem. To be fair, I read about the same problem across many different brands so I'm not sure if other brands are any better. But I've been put off from buying any new rechargeable batteries because of these problems. Not only are they expensive but the performance leaves a lot to be desired.