Eco Divers at the Kima Bajo Resort is an amazing run dive operation! The boats are big enough to allow each person a good amount of space. They assemble your gear for you and change out your tanks and even rinse your wetsuits out for you! The boats have bathrooms (though very basic) and snacks are provided in between dives.
The dive masters are very knowledgeable and there is a dive master per 2-4 people at most. Most of the 7 days we dove there there were only 2 to 4 others on the boat (for a total of 6 max) and the service was very personal. We met the owner of Eco Divers while we were there and he was very personable also.
The diving in Manado at Bunaken National Park is mostly reef/wall though there are a few sandy bottom dives. Most dives would be ok for novice divers (not too much current), though a lot of what is exciting to see there is macro life, which may be hard for novice divers to see as you must get in close. Thought there is plenty of other marine life and the reef is very healthy.
I would dive with Eco Divers again anytime!