No brand preference. My HTC has been good to me but this battery life is killing me. I was first drawn tears the razr for the amazing battery life but the features on the galaxy 3 really shifted my thoughts towards it. And I like the ideal of the 4.7 inch screen too. So Idk really
Have the Nexus now. Ordered the S3 for the wife. Faster processor than the Razr ( &Maxx) and 2gb of Ram. It also has NFC, camera burst mode and better screen. The Razr HD is coming soon if you're a Moto guy.
I'm sure there will be extended batteries for the S3 (but these tend to "deform" the phone). Or you can simply get a second battery to keep as a spare.
So in short, if battery is a big concern, you will have other options. You can always add battery power to the S3, but you can't add S3 features (that I know of) to the Razr.
And with the S3 being an international phone, and nationally on all the major carriers, there will be accessories and such galore.
I was in the same boat as you about a month ago. I was thinking about the maxx because of the battery life but after I did some reading around on the I pre ordered it. The nice part is I pre ordered the s3 is that it's the same price as the maxx so it was a no brainer to order the newest phone.