I was travelling with a friend and we stayed at Le Roof (3* Best Western) in Vannes for 3 nights in August . We found it to be very comfortable, our room overlooked the water sea estuary and had a balcony.
The hotel is located about 3kms from the main old town area. There is a free shuttle bus that takes you to the port/old town area that leaves every 20mins or so. We chose to walk in and back one day and the well-travelled paths meandered through some bush area and then followed the estuary to the port. This took us about 1 hour.
We ate each evening meal at the brasserie that is attached to the hotel and thought the seafood, their speciality, was delicious. There is a small bar, creperie and café (open through the day) located near the hotel.
There is a giant pool, filled by the tides and there were many families using this and the sea estuary as a swimming area. There was also a large camping ground located nearby.
We found the staff to be very helpful and would recommend the hotel to others who would like a peaceful break away.

Comfortable, clean no frills hotel in "L'Ile de Conleau" in Vannes South. Located on the water, next to a park, golf course, down the street from a huge public bathing beach/"pool", and a 10 minute drive to city center. Continental breakfast is pricey, so we went to another hotel up the street where there was a complete buffet breakfast for less money. Food at the restaurant was reasonable and good. While in Vannes, see the old city by taking the "train" , an hour tour of all the important sites/sights.

We used Le Roof as a stop over from South-West France on our way home to the Ferry. It is a lovely hotel in a fab location. Was just a shame that is was raining so we didn't explore the area as we would have done round the little harbour. The restaurant was lovely, best soup I have EVER had! A little more costly then usual but worth the money. There is a cheaper restuarant to the front of the hotel which would be more family friendly. Rooms were very clean, a tad on the small side but perfectly formed. We had asked for a non-smoking room and you could clealry tell that it was/or had been a smoking room but we could cope. I don't think this is a very young family oriented hotel (we stayed with a toddler) but the basics of travel cot and high chair were on hand. Perfect place to stay as a couple. Over all a nice little stop over in a wonderful location!

Good Hotel [ 3/4*] in Superb Location. Stayed 2 nights and would recommend.
However no aircon which would be a problem in warmer months.