We stayed at Ebb Tide with our two daughters (ages 10 and 15), and were absolutely delighted with the apartment. It is immaculately clean, stocked with absolutely everything we needed (including basic food supplies), very comfortable, and on top of all that, very nicely decorated. Lisa, the owner, was a pleasure to deal with.
The location is very practical. A two-minute walk to Southwest Harbor's main area, with a variety of restaurants, bakeries, etc. (don't miss trying Cafe 2/Eat-a-Pita, it was one of our favorites on MDI). And a reasonable drive (15-20 mins) to Bar Harbor and main entrance to Acadia National Park.
The only minor downside was traffic noise early in the morning, as bedroom windows face the main road. One room has an A/C, which we used to keep the room quiet. It wasn't a big deal, but if you're a light sleeper and want to sleep late, be aware.
That said, we were thoroughly satisfied, and would return anytime. And MDI/Acadia is an absolutely wonderful place to visit, especially when blessed with the great weather we had the third week of August.
Thank you, Lisa!