I had also tried the beem library. I found the handling better than with steem-python and it is also a little more up to date.
But I still use steem-python, because I don't know how the developer thinks about the steem-blockchain after the fork. Possibly it is unjustified...
I'm exactly the same. I've played with beem and noticed that it supports Steem and Blurt (as well as hive), but I didn't want to go through the effort of shifting just to have the Steem piece get deprecated. Of course, I suppose it probably has a license that allows forking, so maybe an unjustified concern.
I ended up using beem because I did a couple of BLURT projects. But if you're focused on STEEM, either will do.
I don't think there is any strict reason you should not use beem for STEEM, considering that the developer did not remove Steam class from beem. I think both libraries are good enough and it's a matter of personal preference.