It just seems like in both these places everything is right there. They [Buddy, Habitat] both looked like nice places from what I saw of them. They didn't seem real expensive from what I have read about them.
There is no right or wrong answer here. They are both nice. But there are plenty of other nice places. Everything is right there, but it is at many of the places (or within a short walk/drive). In terms of cost, neither Buddys nor Dons is bad for what you get (although I would argue there are better values out there).
If that is where you want to stay, I am sure you will be happy there. I prefer smaller places for all sorts of reasons. But that is me.
Lets assume four people are in a two bedroom/two bath unit at Habitat is $254/nt including taxes. Buddy Dive has a two bedroom for $281/nt plus another $26/nt in taxes. So seven nights lodging would be between $1,778 ($445 pp) and $2,149 ($537 pp).
You could do Belmar for about the same price as Buddys (Buddy either owns or manages Carribean Club, Buddys, Lions Dive, Belmar).
There is another place, also on the water and also with a pool. Easy walk to Chibi Chibi at the Divi, Richards, etc. You could do four people in a three bedroom (not two bedroom) house for $169/nt plus $22/nt in taxes. So seven nights is $1,337 ($334 pp). You could make that six people in the three bedroom for an extra $31 a night. So, for the same price as 4 people for 7 nights, you could have 6 people for 8 nights.
Regardless, if you are bringing 12-16 people I would at least see what sort of discount I could get. Also, some extras are worth more to some than to others. For example, a breakfast some will regard as key and a huge cost and time saver for them. I never eat that meal so for me that would be wasted money.
Finally, I am sure that regardless of where you stay, you will have another great time!