There are a lot of extremely useful apps that require root. For that reason alone I would say rooting is completely worthwhile. I originally rooted my Bionic, which was my first Android device, to freeze all the crap Verizon puts on it. Obviously that's not an issue on the N7, but now I have so many root apps that it was a foregone conclusion this time around. As others have said, getting OTAs shouldn't be a problem unless you start tinkering with custom ROMs. Sometimes an update can break your root, but somebody figures out a way to fix it pretty quickly. It's rare for rooting to introduce compatibility issues; the only exception I've found is watching live TV on the Time Warner Cable app, which gives you an error message saying you can't do that on a rooted device.
As for unlocking, I'm not as sure. The Bionic has an encrypted bootloader that nobody ever cracked, so I haven't done much exploring in that area. I know you can load up custom kernels, which can provide various performance tweaks, but beyond that I'm not really familiar with the benefits of it.
Of course, before you do any real tinkering, you'll need to be sure you know what you're doing, how you're going to do it, and how to fix it if you break something (i.e. nandroid backups and factory images).