Very powerful, lots of memory, and a very big screen.
Only $200 with activation. I strongly recommend.
I agree but lack of 4g is a real nuisance here in San Diego for Sprint. I stayed with Sprint because of their unlimited data plan but they threw sand in the face of their long time subscribers(2001)just before they released the Galaxy Epic, so do not expect Sprint to have the unlimited data when they roll out their LTE network.
The phone is amazing.
Large screen size is exactly why I dismissed several Android phones in my recent search for a new phone. I want a phone, not something that's too big for a phone, but too small for a tablet. The new RAZR was sweet, and I really liked the case material, but the screen was just too big. As for screen quality, that AMOLED screen on the Galaxys is pretty sweet, but I am enjoying the ultra-high resolution of the iPhone, much easier on my eyes.
As for power, the CPU parts are a bit faster than an iPhone, but the SGX543MP GPU on an iPhone 4S is several times as fast as the Mali 400 MP in the Galaxy S2. iOS heavily leverages the GPU for visual effects, so that GPU really makes the user interface absolutely fluid.
But the Galaxy series phones are generally a safe bet when looking for an Android phone. My daughter just got a Galaxy S with a physical keyboard, and she likes it.