The best bit of advice I can give you is stay away from anything that has fiberglass poles.

Because you've indicated you want to be able to set up on a sandy beach, where you can only stake down in sand, one major problem you'll need to consider is that a big tent you can walk around in and maybe have a room divider in will present a lot of "sail area" in strong winds. This difficulty is mostly solved by using broad sand/snow stakes you can bury deep, but you'll need plenty of strong guy-out points for them and poles that can take the strain. You'll want to think about excluding blowing sand, too. Or you may want to reconsider the wisdom of tenting on a beach in stormy weather.