I've been using mpix for a while and I'm happy with the quality of their prints, but I really don't like their interface for large orders. You have to click each photo to change the number and size of the prints you want, then resave and reload the entire cart again. It's tedious when you have 50+ items in your cart.
In your opinion, which lab has the most intuitive interface? The bare minimum would be something where you can see thumbs of each image and set the sizes and number or prints all on the same page like you can with Walgreens (but with better quality, of course). 
Don't forget to post links. 

