Excellent comparison by the OP. Had the Bionic since release day, and have had a blast with it. I came this close (thumb and forefinger and inch apart) to pre-ordering a Galaxy SIII, then I turned on my Bionic and thought 'why'. While I'd love to have ICS, it will come to the Bionic ....... someday, S-voice does nothing for me, and I rarely take a picture with my phone. As for battery life, since I do a lot of web surfing, I can't see the SIII battery lasting longer than the extended battery currently on my Bionic. Not to mention the fact that I prefer the build quality of Motorola devices. I also find that Blur-lite appeals to me more than TouchWiz, and while I don't root, Go Launcher EX works extremely well for changing themes. To each their own.
I have an upgrade available and may wait on the iPhone 5 since my daughter is now interested in an iPhone. My brother in-law loves his 4s and I know will get the iPhone 5 as soon as it hits, so I'll probably buy his phone for my daughter, then look at the Razr Maxx HD/Vanquish as my next move.