Welcome back, metsmaniac.
I'm also in D3 in Tark, and I like playing zone (and have had some success with it) because it allows some flexibility between 2-3 and 3-2 so you can adjust more effectively to your opponent, without risking a huge matchup disadvantage like you might with M2M. If they ever add a box-and-1 that works effectively, I'd *really* love zone I think.
Rebounding can be a challenge, but if you have a 3 that boards well it can help a lot. Honestly, I think rebounding in general (at least a 3, 4, 5 and guard rebounding helps too) is one of the most important things to look at in a zone. If the other team has a rebounding advantage (talent-wise), that can be tough to overcome in a zone.