What?
I've been using OBMM for years. I've installed (easily and sucessfully) the full set of Qarl's textures, at least 7 UL mods (unstalling three easily when they conflicted with mods I liked better), the latest Vilja, and many more in simple OMOD form. Installing was as simple as copying to my game files and hitting the "activate" button. Uninstalling - completely - was as simple as hitting the "unactivate" button. If I wanted it completely removed, I simply deleted the OMOD after it was unactivated.
Changing load order is as simple as going to the mod I wanted to move and moving it with arrow keys. No mess with figuring out the correct dates to change it to or whether the mod in question has been added to LOOT or BOSS yet.
No, it won't merge lists, objects, or give you an adjunct BOSS or LOOT or whatever tool built in, but most of those can easily be used by themselves. And, it doesn't have new bells or whistles, but it works fine - still. Of course, I install many of the mods manually, but I find it's better to learn how to do this than waiting for patches or updates to the automatic installers when a new mod or update that I want comes out.
I won't recommend it to everyone, but it works fine for people who know how to check for conflicts, read the readme's regularly and set load orders themselves. In other words, it's not broken. It's just older.