I did the upgrade from Bionic to MAXX and after a couple of days with the MAXX, I am quite pleased. The Bionic was a very good phone (underrated in my opinion). The upgrade from Gingerbread on the Bionic to ICS on the MAXX is a slight improvement - more evolution than revolution. The MAXX feels a bit quicker - perhaps this is the ICS at work as the Bionic also has a dual core chip. But the battery power on the MAXX is by far the most important advance. Both days I have unplugged my MAXX at 6:25am, and by bedtime, after 16+ hours of normal to above normal usage, I have had 50% battery left. My Bionic would have died under the same conditions.
To summarize, I am quite pleased I upgraded, and I don't think there's another phone that comes close in terms of battery life. I was close to getting the S3 (which my wife has and is a very very nice phone), but I'm glad I went with the MAXX. I just sold my used Bionic on EBay for $160, so net net, it didn't cost me much for the upgrade (Verizon gave me an early upgrade for $199 since I b*tched about Bionic's new estimate of 4Q for ICS).
PS- I dont understand why used Bionics sell for $160 on EBay. Used MAXX's sell for $350. Can somebody explain why used phone prices are so high?