I wrote a long trip report after our July 2005 trip; you'll probably find it with a basic search. Wife and I absolutely loved Saba diving.
I don't have any feedback regarding Sea Saba aside from 'we saw their boat'. They were a bit bigger (I don't think I can quite say 'cattleboat' not really knowing how they were laid out) than I'd prefer, and it seemed like they hung out for their surface interval rather than going back to dock.
We dove with "the Mikes" (and Oliver) at Saba Deep, and I couldn't begin to recommend them more!! They take smaller boats, moor and dive with you. We never had more than 8 divers total and generally it was more like 4-5. Most of the week my wife and I dove with a husband and wife who were both doctors from S Carolina who go there every single year for two weeks straight. Wonderful people. Another day we got to dive with one of the locals who runs a glass art shop near El Momo (Jobean). Basically if Saba Deep is the local's choice, that says a lot in our book... And Sally and her helper's cooking at their restaurant (In Too Deep) for lunch was also superb; perfect break in the day between dives 2 and 3!
Saba Deep just runs a small boat (open top with a half-cover on it), but don't be fooled by all the spouting about 40' luxury ships from the other guys...the slope off of Saba is so steep most of the dives are within about 10-15 min from shore even on a little boat...you're not there to pay someone's yacht mortgage after all, you're there to dive!! Again, I've got nothing BAD to say about SeaSaba, as I have no experience with them. I just loved the personal experience with Saba Deep too much to even consider anyone else (narrow-minded bahstid, I am

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Housing is semi-limited on Saba in choices. I think there's just like 3-4 hotels, the rest being cottage rentals. The Gatehouse hotel is gorgeous, but way on the airport side of the island so its a bit out of the way. You'll need a taxi or ride (maybe they provide, I don't know) to visit much else from the hotel itself...Saba is VERY mountainous so even extremely short hikes seem waaaaay longer

. Princess Juliana Resort from what we saw is similarly very nice, and more centrally located (the Dr.'s we dove with stayed there). I don't know anything about the Willard's place other than that people have said its pricey, or Scout's Place (?? is that even the name or still there ??), and at the very top o' the mount is the Ecolodge which is a bit more adventuresome, and probably a bit awkward for getting to early morning dives.
At the lower-cost end, we stayed at the El Momo cottages, which were more a 'backpacker'/eco-friendly type stay. I'd have to say we wouldn't do El Momo again in July - no AC and only small fans in the cottages, and a rather lot of noise from insects/frogs and the like at night, so if 'camping' isn't your thing you might want something a tad nicer. No real complaints, great hospitality and nicely maintained for what it was - it just wasn't quite the right choice for us (and I've heard its up for sale too, which is kind of sad even though it wasn't our cup-o-tea - the owner made a wonderful tropical banana spread and a wicked banana rum as well!!)
My suggestion: contact Saba Deep and tell them what you're after. There are rental cottages and other choices to be had for lodging if you're staying at least 3 nights. "Little" Mike was absolutely wonderful about giving advice and he and his wife Sally actually set up our reservations for us, as well as setting us up with a taxi driver to make sure we made it to the dives each morning (even if you did choose the Gatehouse, it's not like you're on the other side of the planet - the island just ain't that big).
Really I don't think you can go wrong at all wherever you stay, just consider your willingness to get up a bit earlier and/or have to hike a bit to get to where the taxi can meet you (our walk from our El Momo cottage to the road was only about 60 yards - of very steep stairs...ouch! Woke my knees up in a hurry each morning!!), and whether you want AC and real hot showers or not, and you'll find something right for you. Worst comes to worst, you learn (like we did) about the lodging, but you'll get another chance - the diving is worth going back for again. We certainly plan to sometime!!