It'll be a little scary when you do it for the first time. If you have a friend nearby who's done it, get them to help you out. I had the original Nexus One and even though it's easy peasy to unlock and root, I was totally freaked out the first time that I would brick it.
![Eek! :o :o](/styles/smilies/google/eek.png)
But pretty easy all in all. I believe P3 will provide a one-click root soon for the VZ Gnex.
Remember that unlocking the BL or rooting doesn't change the software (ie: doesn't impact stability) but allows you to install kernels or modify/install root level programs. It's when you start flashing custom ROMs you may run into some stability issues. I think I'll enjoy stock for a bit and then see what's out there.