I've had this phone for about a month or so, coming from an iPhone 4. All I have to say is the Galaxy S2 has impressed me so far. I love the size of it (coming from an iPhone, it's a bit odd, but I'm getting used to it), how fast it is, and the design is pretty nice too (not as good as the iPhone 4, but still good nonetheless). I would recommend this phone to someone who wants something fast and reliable.
Pros: Built-in speakers, Bright display, Realistic color, Lightweight, great size, front-facing camera
Cons: no home button (like the international version)
Power downs randomly, gets hot, freezes. Sometimes even power key becomes unresponsive I end up removing battery to power down. It looses wireless connection until I remove battery. I switched to this phone from I-Phone thinking this would be better, breaking the itunes mess but I did not expect this.
Pros: nice paper weight
Cons: Poor quality, Did not meet expectations, buggy
Great, powerful phone. My son has this phone. Had it for 7 months and even with his carelessness it has withstood it all. Was easy to set up out of the box. Has a great ergonomic feel to it and materials are superb. Expandable memory, battery choices and other options. Updated to 4.0.4 through kies and it's even better.
Phone works great...apps aren't nearly as plentiful as with an I-phone but are improving as time goes by. Sound quality is superb and I have had no problems with this phone dropping calls.