I've been on the Sterling a few times...It's not too shabby. Of course, it's free, so that helps.
I think there are five or six levels, lots of slots and quite a few tables. There are a handful of tables (blackjack, poker, roulette) where the minimum bid is as low as $5 or $10.
There's some free food -- snack like stuff. Cheese and crackers, little mini-sandwiches, etc. And once you're three miles out - legal gambling territory - the drinks are free, too.
I'm not much of a gambler. I'll go with friends who are a little more hard core. I'll take $20 and that'll last me for the evening -- I'm a big fan of the nickel vidoe poker. Plus, it's kinda nice to sit outside on the upper levels and just hang out.
Another thing, call ahead to reserve your tickets (even though they're free, you need to make a reservation) and be sure to bring a photo ID or they won't let you board the ship.
Hope this helps.