Others say...

"Excellent Flash- but get MAHA battery/chagr and a frame"
This is a great flash for the xti. Use it instead of the on board flash, because it will add dimension to you photos.

At parties, or weddings, use it with a frame.

I use maha rechargeable batteries with this flash, and It has not failed to provide great photos.

The only thing that I would improve would be to give it a optical slave response, that way the on board flash can be used to trigger the main flash. Alas, no luck. Glad it has remote cable trigger though, for studio work.

Over all, I am pleased with this flash. When Canon comes out with an update, I'll gather up a few more of the ex2's.

"Canon quality"
The 580 EX is a great product! Easy to use and gives great results. if you are thinking about getting one, do it! You won't be sorry.

"Permanent Accessory to my camera!"
This flash is incredible! I pair it with a Gary Fong LightSphere & it is the most natural 'artificial light' you could ever wish for without the hassle of studio lighting! You can basically mount it and turn it on, producing wonderful results... But with a little homework to learn the many features available on this flash, you can create wonderful lighting effects! Worth the investment!

"A great flash, but make sure this is what you need."
Bigger is not always better. The more you pay for a piece of camera equipment does not necessarily mean you will get more out of it than a less expensive alternative. These are two axioms that I wish I could learn someday, but I guess some lessons have to be learned the hard way.

This is a great flash, don't get me wrong. It's a 5 star flash--if it is what you need. I bought this thinking it was what I needed but as it turns out it is too big and too powerful for me. It is extremely large, powerful, and top-heavy. I sold it back on the used market and picked up a 430ex which comes in at almost half the price. The 430ex is also around half the weight/size but still packs a good 60-80% wallup of the 580ex II. For me, this has been ideal. The 430ex provides enough flash but not too bright, and it isn't top-heavy or attention-grabbing like the gigantic 580ex II.

If you are going to be photographing celebrities, people who are far away from your camera, or other situations which call for a very powerful flash then this is the flash for you. If you are looking for more of a wedding or cocktail party flash, then I believe the 430ex is the flash. It is hard to tell from the pictures just how different the sizes of the two flashes are, so I didn't know the 430ex was such an ideal size compared to the 580ex II.

While I can't say anything bad about this flash, just take another hard look at the 430ex unless you know you need some serious flash-power.

"Buy this good flash first before thinking of investing in any lense"
This can be had for as low as 350 USD.

After buying, play around with the curtain sync settings, bounce, and diffusers. You'll immediately see payoff in your investment, through quality pictures.

This is really indispensible at indoor shooting.

I also see improvements in battery and recharge time compared with make I of this 580 model.

You cant go wrong with this investment.