We had a two week stay at Anu's lake house with a 6 person family, and we had a great time. Located in a small quiet area with a few houses (spread wide apart), the house is spacious and airy, with a private access to lake Hiidenvesi and a great view of it. The house has a fully equipped kitchen, a TV with a gaming console, a large dining and living room, a wood-fired sauna, two toilets, a shower, and plenty of room.
At the front of the house, there's a nice grassy open space for kicking around a soccer ball, and an outdoor dining area. In the back, there's a nice covered barbecue space with both a gas and wood grills, a deck with a table and beautiful view of the lake, and a couple lake access points with a row boat that can be used by 3-4 people.
The supermarkets at Nummella (Lidl, K-Market, Prisma) are a 15 minute drive away. The drive to Helsinki is about 35-40 minutes.
A couple things to note that are normal for country living: water should be used economically, as the house has its own well, which can run low (the kitchen has a dishwasher to help save water). Also, there is no wifi, but there's great coverage by major providers in the area (Elisa, DNA, Telia), and unlimited access is cheap (we were using DNA SIM cards that give you unlimited everything for 90 cents a day).
All in all, we had a wonderful experience. The house was clean, quiet, with all the amenities needed for a relaxing vacation. We rowed the boat, cooked for ourselves and dined outside, played soccer, walked down the road to the horse farm to pet the ponies, picked raspberries, currants, and cherries that grow around the house, and took day trips to different destinations in the area (Serena water park, Helsinki, cave formations, Nuuksio park, etc.) Jari, Anu's husband, was easily reachable by phone, and helped us quickly deal with a couple snags we had. This house was perfect for a relaxing family countryside vacation, and I would definitely want to visit again!