I originally had my boat in the Med (Toulon) and never regretted bringing it to S. Brittany. In the Med there is either too much wind or none at all and you often have to get into port in the early to mid afternoon to ensure a berth.
My berth in Lorient (Locmiquélic) for a boat (<9.50m) is approx €1400 / yr - electricity, water and showers are free. No extra charge for storage on land (except haul out costs). Free overnight reciprocal arrangements with about 10 other ports. Locmiquélic is extending its marina this winter to create a lot of new berths. The staff members are very friendly and helpful. There is an airport at Lorient though not for Ryanair.
The cruising area is superb being 4/6 hours away from Belle Isle or the Iles de Glénan.
we left our 32ft yacht at Chantier Michel near Grau Agde on the River Herault.
Small basic friendly well priced place to leave ashore. We flew Southampton to Toulouse with Flybe for £9.99 and got train to Agde.