We stayed at
BelMar condos (wow almost 5 yrs. ago) so this may not be current. But given the exceptional staff there, I doubt it's changed much. The condos were nice, very clean and very quiet. Mostly full kitchen (missing an oven as I recall) and not crowded at all. We stayed in one of the ground floor 2BR units it opened right out onto the pool and 50' past that was the dive dock. Neither bedroom had an ocean view, the master is at the back and the 2nd bedroom is in front of it. Great sunset views from the livingroom or patio as they face west. Belnem is pretty quiet at night.
It's a pretty compressed property, there's the main building and then an office/diveshop area immediately off the parking lot to the south. The tank pickup is 20' off the street there as well as gear storage/rinse area for anyone with an upstairs condo - the first floor units all have a lockable closet outside your back door.
The other Buddy Dive shop is on site - when we were there it was Toucan (at the Plaza) so we used Toucan.
The Plaza is a big resort with a long walk from some of the condos/rooms to the onsite restaurants. Also the diveop/boats are on the lagoon on the south end of the property and their shoredive (18 Palms) is near the north end. They deliver tanks there but it's not something I'd want to walk with gear. I have heard sometimes you can get a ride in the staff golfcart. They have a small fleet of newish diveboats and were never crowded.
But you probably get a better deal with Buddy's if you stay at BelMar. And if you're diving north, you can change tanks at the Buddy drive-thru.
Back to BelMar. The house reef is good enough that we did it twice. There's a rinse tank and tanks right on one of the two dive platforms and easy steps down into the water. No beach at all the entire resort sits about 15' above the water on ironshore. The waves breaking on the pier at night are audible from your condo. There's a light in the water for night dives - if you have one of those little strobes there's a ball you can tie it to a short distance out.
All the really good southern dive sites - Alice in Wonderland, Invisibles, the Hooker, etc. start about 3mins. south of BelMar on the same road. So if you're diving in the south, you pass BelMar on your way north to change tanks etc. For this reason, we just threw our gear loose in the truck and didn't need to lock anything up all week.
Downside of BelMar - and Belnem in general, is that there's almost no where to eat within walking distance. One small restaurant at another resort just down the street was all we found for breakfast. It was a 5 min. drive back around the lagoon (not really walkable) to the Plaza resort area or into town for just about every meal. Plaza has a restaurant and beach bar and there was a little snack shop just across from the entrance, they would do sandwiches to go if asked. If they still do the BBQ Friday nights at the Plaza, it was a good time.
I don't know if you're considering Port Bonaire condos also, but know they're in the flightpath. Belnem is far enough south that it's not an issue. Check out divervince's place -
http://www.bellevuebeachbonaire.com/ - if you're looking for something a little more upscale in that area also. I think I'm staying there when I go back.