What makes you think the Galaxy S2 is the best Android phone?
It has better hardware and might be a tad bit smoother than the Nexus but I think ICS + a 720p screen more than make up for it. Plus the Nexus is schmexy.
Hardware: super fast, no hiccup, smooth overall not just tad smoother. Can run anything. Its on par with the iphone 4s and its been out since May. No other android phone is more powerful....err the Note if you consider that a phone...
Camera: only the iphone 4s is better. Gnex have a really crappy camera. The no shutter is a gimmick, because to actually make the picture decent, you will have to focus which add shutter time.
developers: If you got the exynos, there is more roms and mods than the gnex. Plus the Gnex takes forever to back up and restore via nanoid. I never had a random reboot with the GS2 while I had random reboot with stock Gnex. Alot of developers are sticking with the GS2.
Super amoled +: 720p super amoled is nice but other than watching full screen videos, it wasn't really that useful. Unless Im watching 720p videos the screen won't be full screen because of the soft keys. The color is much more vibrant and brighter on the GS2.
Reception: Gnex reception sucks kinda...i tried multiple base band.
Speaker: GS2 is louder....Gnex is kinda on the low side.
All this and its a tad cheaper than the Gnex.
My Gnex is gone when the iphone 5 or GS3 comes out.
But still.... the Gnex is too dayam sexy though...I'm so proud of my tuna..