Sand Dollar is on Bari Reef - one of the better shore dives. It's also directly across from Klein Bonaire. Sand Dollar is among the dive resorts north of town - a short drive to downtown.
BelMar's reef is an extension of Bachelor's Beach - a good dive but not something we did more than twice. BelMar has the advantage of being 50' from the water - we left the patio door open at night to hear the waves breaking. BelMar sits slightly up on the ironshore so there's no beach - just stairs down to their dive dock and sundeck. For a beach, you'd have to walk over to Bachelors Beach - no idea what it's like. BelMar is in BelNem, a quiet residential area south of town.
From what we saw - not much beach at Sand Dollar either. But there is some sand among the ironshore IIRC near the south end of the property. We didn't go near the main portion of the resort as we were diving with BD&A - they're located on the south end of the property.
The other Buddy Dive operation is at BelMar. So you can use the drive-thru tank pickup at Buddy Dive when diving north of town. And boat dive with them also if you buy that package. Buddy definitely has bigger boats than BD&A.
BelMar's pool is between the condos and the water. We had one of the middle condos on the first floor so it was 30' from our patio. Sand Dollar's pool is in the parking lot - the view to the ocean is blocked by the condos. In our BelMar condo the master bedroom was in back so the view is of the parking lot/neighborhood. Unobstructed view out to the ocean west from the living room, we watched the sun set off our patio.
If you're getting a first floor condo at BelMar, you'll have a locking dive closet just outside your back door -your condo key opens it - from there it's 30' to the parking lot. For 2nd/3rd floor units, there's dive lockers at the south side of the property in/near the diveshop. When we were there, lockers were outside by the rinsetank and suit hangup storage was inside in the public area. Your condo key also lets you into the public areas of the dive shop so you can use the Nitox Analyzer, get tanks etc. - 24/7 - at least it did when Toucan Dive ran it - that was a few years back. Tank pickup for shore diving elsewhere is at the south end of the parking lot - it's a very compressed property - Buddy's stages tanks on the dive dock for house dives - air only as the analyzer is in the shop.
From what I've read BD&A closes up around 5:00 so you need to get tanks and store them for night dives. But you could just throw them in the truck - we left tanks in ours all week. No one steals them since no shop will fill another's.
Parking is real tight at BelMar, one car per condo. BelMar looked to be the newer property also.
Sand Dollar has more nearby dining options, in addition to their restaurant you could walk to Sunset Grill at Den Laman, Lions Den at Buddys, Rumrunners at Capt' Don's or Bongoes Beach Bar at Eden Beach. There's also a bank/ATM, Lover's Ice Cream and small market just south of there within walking distance.
BelMar is past the airport south of town - there's only one restaurant nearby that I'm aware of. The next nearest food would probably be at Plaza Resort or a couple minutes further north to Kralendijk. Since there's a lagoon between BelNem and south Kralendijk, you have to drive as the road jogs inland first - watch for the donkeys, they hang out there when they get out of the sanctuary. And are used to being fed so cluster near the road. No streetlights either IIRC...
I'd stay at BelMar...