We recently stayed at this cottage and overall, it was a great place. It definitely can hold a lot of people, although the adult count probably should stay 8 or lower to be comfortable. There are tons of comfortable chairs on the deck, around the fire pit and by the water. The Kayaks were good as were the paddle boards - allowing you to roam around the fairly small lake - doesn't have much boat traffic on it at any given time, which is nice. The lake is extremely shallow and warm and not rocky at all - so great for kids. It's very quiet and peaceful - development along the lake isn't that intense and there are long stretches with no cottages at all.
This also brings one of the downsides - cell reception is lousy - and that's an issue because the included wi-fi is fairly slow, and is capped - a challenge when the place is built for a lot of people - a lot of data is used. Also, the cottage is located off a "use at your own risk" non-maintained road - pay attention for the rock and holes that could cause issues for your vehicle.
For the most part the kitchen is well stocked with the non-food items you need - you really just need to bring up the food and drink.
I found the bugs at this spot to be worse than my typical Muskoka experience - all but one night we were driven in about 30 minutes into the camp fire - even with DEET. For the most part, the bugs weren't a problem during the day.
The games room is of good quality overall, and can help deal with any lousy weather that pops by.
It's not mentioned anywhere that I saw, but the cottage is not air conditioned. Some days this was a pain, others it wasn't. Wouldn't not stay here because of this.
If you need a big cottage with some nice touches, this is a great option that I would seriously consider returning to next time we are headed to Muskoka.