For anyone that has driven, say, between Barcelona and Nice on the Spanish Autopista and French Autoroute(s), how are the service plazas? For example:
Are gas prices higher there than on the local roads and in towns?
Do they have decent places to eat?
How about cleanliness and safety?
Do they seem to have enough service plazas scattered along the routes?
I've driven on several of the Italian Autostradas, and their service plazas were generally first-rate in every way (I don't recall the situation with gas prices, though).