I'm assuming your list is there for a reason so I'll stick to it. And this is just my opinion, so take it for what it's worth. First off, remember all of these phones EAT battery life on 4G LTE. It's fast when you need it, but you'll need to get an extended battery, extra battery, or be near a charger all day to keep from running out of juice before the end of a normal work day.
As to the phones:
There's no question that Motorola, hands down, makes the most physically solid phones with the best radios. The Bionic is a good phone, but there are big questions as to when it might get any software updates. I don't know about the Droid 4, but it's only big selling point is that it's got a physical keyboard. Otherwise, it's not really much for me to get excited about.
The Nexus looks good on paper, but I've seen allot of complaints about the radio on it not working well. Dropped signals and calls seem to be a big issue.
The Rezound has the best screen and the neat inclusion of the headphones and Beats Audio. But, it also eats battery.
The Charge is not even worth considering, to be honest. It's not even in the same league as the others. It's specs are WAY out of date.
I had the Bionic and I sold it and bought a Rezound. IMO, that's the best one on your list and you won't go wrong with it.
Finally, when in doubt, go to the store and hold them in your hand and look at the screens yourself to see what you like best. In the end, it's your phone for 2 years so it needs to be one you like.
