S3 didn't impress me
I'm an owner of the HTC One X and at the time I got it one of the thoughts I had was along the lines of, "I wonder if I should wait for the S3." I've owned three HTC phones, that includes the One X, and I'm a fan of the Sense overlay they use in general but if a rival handset came out that was unbeatable I would likely jump at the chance to own it. Compared to a stock Android experience Sense adds quite a bit although prior to Sense 4 the home screen wasted a lot of space on three, non-customisable buttons.
Unfortunately for Samsung their big S3 launch spectacle was just that, a spectacle. Nothing on their new phone made me go, "Wow! That's going to sell millions." I can still see it being a popular phone just as the S2 and original Galaxy S were but it isn't going to tempt me from a phone I'm very fond of now. The biggest stand out feature to me is one that I can easily see being somewhat widespread in a year and that's the one that keeps the screen on while you're looking at it.
I don't see non-Samsung Android owners looking at it and being all that impressed. It feels very much like the iPhone 4S in terms of slight updates in specs compared to the previous release. One thing I don't see mentioned anywhere is what happens if Apple lose their cases. Are they made to compensate HTC, Samsung etc for lost revenue, missed sales targets and share price loss?