I just bought a Razr Maxx HD yesterday. I came from a Samsung Charge, which I really hated.
After 24 hours of use, I am far from impressed. The phone came with 4.2 JB and the real reason I bought the phone was battery life. With what I would call moderate to aggressive use of the phone, the battery was at 33% at 11:30a and I didn't pick it up until 7:30a.
The processes by the specs should be twice as fast (i.e. more ram, twice the processor, etc) but it is about as fast as the Charge and there can be a lag on the phone where any button is pushed and it does nothing for about 10-15 seconds of repeated pushes.
If there are tips or tricks that I should know for battery use or speed, please let me know. At this point, I have 13 days to return the phone and unless something changes, I don't see a reason to keep a phone that I have to fiddle with the settings (which is why I bought in the first place, to not have to) to get a work day's worth of use when I can just strip down the Charge and get the same speed and battery life...........but I get my $200 back.
Motorola's Smart Actions, Battery Saver, have greatly improved battery life on my Droid Razr Maxx. Also, Gravity Pro Screen Off will turn off your screen, one of the biggest battery consumers on your device, when you lay it down.