Every phone tends to be specific when it comes to roms on how it is done and what ones work the best for the device. Sometimes you will find a Rom for one phone works awesome, then someone will port it over to another device, make all the necessary changes and it sucks horribly. If you do do a custom Rom, you will no longer be able to do updates from verizon unless you are just running a debloated/rooted/deodexed/or what have you rom that is still the stock rom at the OS level.
Custom roms are really just ways to add other features from other devices (like ink lockscreen), theming, performance and battery management. Is it worth doing, yes if you are bored and want to learn a few things sure, is it totally worth it, no; Alot of times the best roms are the stock debloated and rooted Roms in all honesty, at least then all the features of the phone tend to keep working. With a rom like that you can then mess with the kernel and put different cpu governors inplace/change more pertinent settings with the phone/and increase performance. There is a number of reasons we all do it.
As far as how-to's, XDA forums is your best bet. You can often google your phone plus the name of the rom and there will be a youtube how-to video.
Here is the HTC Rezound section on XDA
http://forum.xda-developers.com/forumdisplay.php?f=1389
