I agree with your remarks with regards to 'non-specialist' high street outlets or supermarkets. These sort of places can't afford to employ skilled technicians and rely on button pressing kids fresh out of college: look at how many truly professional labs have gone out of business in the last few years. There are a few good labs still around and unless you're lucky and live near one then you'll have to deal with them by post - I'd guess you already do that for your slide processing? I use The Darkroom UK but Peak are good too.

As regards reproducing sunsets etc. I had a friend who was complaining his prints looked washed out compared to his monitor. I popped round to look at his monitor and realised why: I practically needed sunglasses to look at it as he had the gamma turned up so high it looked like a stained glass window! No way paper prints can reproduce the same range of tones as a monitor, or slides come to that.