I've seen that quite a few mods require Wrye Bash, and was just wondering if this was compatible with OMOD, as I think they both basically do the same thing? I'm reading through the "manual" for Bash, but I can't find ANY mention of OMOD on there (as a lot of mods require OMOD to work as well).
There are no mods that require Wrye Bash in order to work (or even install)... except
maybe FCOM, to get it working
properly. Not sure, even then. Perhaps Wrye Bash simply makes that easier. Not that I'm willing to put that to the test, however.

OBMM is a different application, that installs and/or organises mods in a different way. You don't need that either, except for mods that are only available as OMOD files (literally, "file_name.omod".)
OBMM is
much easier to use, but you can do
much more with Wrye Bash. Using both is quite OK as well, and not at all uncommon.
edit: A very common setup is using OBMM for installing and organising to begin with, and Wrye Bash for patching, debugging and tweaking. BAIN (Wrye Bash's installation section) can be used in place of OBMM, and is overall much better in many ways, but requires some reading and learning. So Wrye Bash can be the one and only of its kind - this is how I like things, since I started becoming familiar with BAIN. YMMV.