FOMM has recently become a bit unstable. Especially the Package Manager and it's inability to update fomods. And after installing NMM it's down right unusable with all it's frequent crashes and CTD's.
However, NMM isn't without its flaws. NMM doesn't handle scripted fomods very well as it crashes when I attempt to reinstall the missing mods. But I suspect this will be remedied in later releases.

So I guess my question is, reinstall FOMM and sort out my fomods from scratch? Or try to make NMM work and install scripted fomods manually?

Info:
FOMM - FallOut Mod Manager
NMM - Nexus Mod Manager

Imho, I would stay with FOMM. NMM is still in beta testing, which is fine if you want to be part of the test group and report all the problems you might have. Personaly, I have not had a problem with a properly installed FOMM. I tried NMM for a little while and uninstalled it because of problems with that progam and the problems it caused with the game. I used it for about a week and than went back to FOMM. What it comes down to is your personal preference.

The reason for trying NMM was that FOMM started to behave oddly. The Package Manager stopped looking for updates and sometimes crashed. Dunno why really. BOSS updates? Using NMM only made it worse for FOMM, so they're definitely not compatible
Anyways... thanks for the input M48A5. I'm reinstalling FOMM and redo all my detailed mod-info again.

I'm going to bump this back up and pose the question again. NMM has updated a few times over the past couple of months and seems to be working pretty well with FONV and Skyrim, but does anyone have any more current info on its ability to handle/work with the older FO3 packages? I've used it for a couple of fairly standard mods (Unofficial Patch, WMK and a couple of other minor ones), but nothing heavy like MMM, FWE or stuff that's really picky on load order. I notice that it's grabbing an updated BOSS list just about daily, but suspect this is more for TESV. Thoughts and comments? Thanks.

Some people have reported issues with NMM not handling a few older fomods but if that happened, you could rename the fomod into a zip file and open it up and make your own fomod from the archive to install it.
I have yet to try NMM preferring to stick with an older version of FOMM (13.10) and Wrye Bash.