I finally got the Sims 2 Ultimate Collection from Origin today! I've been meaning to transfer my Sims 2 game from my laptop to my desktop PC for a while now (laptop's specs aren't quite up to running the game at a good capacity, esp. with a lot of CC) but I would really like to transfer the neighborhood I've been building for over a year to my desktop game if I can. Only problem: I never bought Bon Voyage when it came out, so my neighborhood is missing one of the EPs. I've tried to look up whether you can transfer stuff to games with more EPs and I've found a hesitant yes as an answer? (And a definite no on transferring to a game with less EPs, which -> logical)

Can I still transfer my non-BV neighborhood to my new UC game or are the files not compatible? (If it matters, I have every other EP and no stuff packs)

I'd say yes, no trouble. Like said, there would be a problem if your new configuration was missing an EP, but with the UC, this won't be the case.
Likewise, if you had The Sims 2 Store Edition, this will cause problem and special attention will be required. Otherwise, all should be OK for you.

Alright, thank you! I'm gonna give it a go then :D

You can also visit many other threads about moving to the UC, it is trendy nowadays on these forums
And you are welcome!