Only had one night, wished we had more. Ascona is a great spot and we throughly enjoyed our stay. The Mirador is 5 minute walk to the main promenade on the lake front. If you are thinking of staying in Ascona then there are a number of lake front hotels with lovely views I am sure, but when the Hydrofoil ferry comes booming into town you know it. Therefore ,for us, being a street away sheltered us from the lake noise and made for a great stay.
The staff were great and provided service beyond our expectation.
A nice way to relax is to have a beer (or wine) in their beer garden.
The rooms were comfortable, and what was nice was having a couch to sit on, even though it did take up some floorspace.

Very warm welcome, although we only arrived around 21:30. The manager of the hotel came to pick us up at the bus station. Very nice neighborhood, full of luxury residences and villas with huge and nicely taken care of gardens. The hotel is spotless: the cleaness is just a-m-a-z-i-n-g. Breakfast is also extensive and the service is just irreprochable. We got anything we wanted with a smile and warmheartedly.
The only negative point we see is the size of the room: relatively small. But then we were the whole time away. Could be a handicap in case of bad weather.