As for the viewing quality and use of racks-first off, I agree with everything Shannon said in her last post,
and my addition is;
depends a little on what tubs you use, but yes, display tanks do allow much better viewing.
My honduran milks and corns ate at eye level in sterilites, and I can see them quite well. Others, down at floor level, are not so well seen, but then, neither are the ones in glass tanks at floor level.
As for the performance- I have had many, many species of snakes thrive in racks. My infernalis, fitchi, and marcianus are all in sterilte tubs- and are eating machines. They will be upgraded to glass tanks when they get a little bigger, by this summer. Nearly all my garters were started in tubs.

I just moved my albino gopher out of her sterilite- she was docile as it gets and never missed a meal. Now she is in a glass tank, with a hide box and deep aspen bedding to crawl through- shes meaner than crap and wont eat. I hope she'll settle down, but if not- back in the rack she'll go.

The truth is, I used to think racks were cruel, until I tried it and saw how my snakes did. Generally speaking, they thrive. They seem to feel more secure, in the case of many snakes (not garters so much), it is a closer comparison to how they live in the wild- hiding in cramped quarters like many snakes I have found. Just like how hideboxes that are cramped actually seem to work better than nice roomy ones. More security.

Ideally, I would love to have every snake in a nice display tank, but first and foremost, with the variety of species I keep, I first do what it takes to get the snakes acclimated and feeding- and the racks win that one so far, for most species.

James- most definitely not argueing your point- I love to see my snakes, and cages like those that you built are definitely the best for that, and do provide the snakes a great home that looks great as well.