I spent a week at MantaHouse a couple of months ago, stayed in their North Bungalow.
I guess it all depends on your standards and expectations. All things considered I found it roomy and reasonable, we had everything we needed with a full kitchen (fullsize fridge, stove, dishes etc). No issues with basic stuff like hot water or power supply. You have front and rear patios and places to rinse and dry your gear. The ladies running it are friendly,helpful and accommodating, and as noted elsewhere, its very handy to the dive shops and to town.
That all said, its pleasant enough but not "posh" in terms of decor or amenities. There was an extra sleeping spot in an elevated area near the kitchen, but do know that only the bedroom had AC. Of course that is less an issue if you are only using the bdroom, also less of an issue in Dec. We were there in June and I have to confess even with a nice breeze much of the time the rest of the apt could still get a bit toasty. Still its not a bad deal.