Tony's description of a restaurant gig pretty much parallels my experience except that I don't play in an 'upscale' restaurant ... light and soft to start and a party-like atmosphere when the wine kicks in. This is the only eatery gig I currently have partly due to, I think, the heavy handed BMI tactics in my area. I've been at this particular restaurant 11 years, down to 1 night a week. The exposure and the resulting private bookings gotten from the restaurant gigs may be worth the less than stellar pay.
Ciao,
Jerry