I have compared the Rezound to the Nexus on several occasions (a few of my friends have them)... in my opinion the newer OS and larger screen are not worth it, the Rezound is a much higher quality device, better screen, camera, build quality, etc. JB will likely come to the Rezound, whether it is an "official" build or a custom ROM is what remains to be seen yet, but if you are willing to root and go into custom ROMs, almost every JB feature is available on the Rezound right now, including Now!
Speed wise the two are fairly comparable, although the reception of the Nexus can be spotty, in poor signal areas I have seen the Nexus unable to load web pages, text, or make calls, where the Rezound has no problems with any of these.
But then again, for $100... that is pretty reasonable and the Nexus is a solid device. The other option is drop the $100 for your buddies device, get yours repaired (you can probably find a local/internet place to do it for less than the insurance) and sell one or the other on eBay/CL/Swappa, you will probably wash and essentially get the one you want for nothing.