I have been happy with Tunze 9010 on the 120, compact and can be converted from in-tank to in-sump with much ease.....
I also have a BM250 and am happy with it as well so BM160 maybe an option as well for in sump.
I am sure there are others that are equally good, but I think skimmer in this hobby is like a goodwill curse. No matter what you get you will always feel you should have gotten a different one, even if you don't admit. But reallity is the one you got is just as good as the one you didn't get.