Hi Jason,
I can't comment on Alor Divers on Pantar as I never dove with them but in my opinion they have been too expensive and are far too remote.
If you stay in Kalabahi, the main town on Alor, you at least have a chance to see something else or walk around in the evening. On Pantar is, from what I saw from the boat, nothing.
I was on Alor around March/April, June and November (multiple visits of course) during the last years and never had bad visibility (= less than 20m) or bad weather. It all depends on the dive-sites you choose ;-)
If you have a chance to dive on a house reef it's a nice to have but, honest, the best dives have to be done by boat. And considdering the depths you have around Alor I won't dive more than 3 (boat) dives a day which you can do with all operators around Alor. Keep in mind that you are pretty remote and currents can be strong.
Have a look on the boats they use for diving, too. Alor Divers have, as far as I saw, only a speed boat with not much room to stay during surface intervals. Alor Dive, the German dive operator, on the other side has a large boat with kitchen, toilet and lot's of space to relax (and fish) during surface intervals. As you can't do much on Alor besides diving the trip to the dive-sites which of course takes longer from Kalabahi than Pantar shouldn't be a problem.
In any case: Don't go to Alor with a live-aboard. The guides don't know the area that well and therefore you don't get the best divesites or, if you are on those, not at the best time ("Kals Dream" can be the best or the worst dive, depending on when you do it during the same day).
HTH,
Andy