I think female bettas are generally okay with other community fish. I've ~8 female bettas in my 50 gal community tank. They get along well with my other fish (incl angels, tetras, cherry barbs, rainbows). Sometimes the female bettas do chase around. But if you have enough hiding place for them it'll be fine.
For male bettas, since their tails are big, they are slow swimmers (compare to their tankmates). Their big tails will also attract other active small fish to nip them. One other concern is that betta (esp male betta) are not as 'greedy' as the other fish. So when you put him in a community tank, the other fish may get his food before he can get it.