At least one of the photo-processors round here (Jessops) offer a manual individual inspection and adjustment during the printing process. It costs an extra 1. On the rare occasions I shoot C41 I generally go for it. Bear in mind though that the "inspection and adjustment" usually takes about a second per frame, and I've still had pretty ropey results...

A few years ago I shot a sunset at Morecambe Bay. I had a roll of Fuji Reala in the camera, so I finished that off and then reloaded with Velvia. The Reala came back first and I was gutted. They weren't even indifferent. They were just plain awful! Then the Velvia came back containing some of the best shots I've ever taken. (I know Velvia is super-saturated and Reala isn't, but that wasn't nearly enough to account for the difference!)

Like I said earlier, I don't shoot much C41 any more...