Quite fragile, but nice, I've used to mount some images "floating" ie on a mat board slightly smaller (12x18"=size of image) than the print (13x19"), itself raised from the back mat (18x24") by some foam core.
The corners of the print are exposed, but I like the effect, and it's much cheaper than other methods.
It's also lighter - I wouldn't want to think of a 18x24" glass frame falling on one of my kids (or anybody else).
And above all, I really dislike affordable glass too, and still find the print itself more attractive bare than behind some crazy expensive glass.
Edit : even if the end of the world may take place in 2012, I still protect matt prints with hahnemuhle spray. It seems to add a fair protection to aging according to current testing at AadenbugI&A, and the aspect of the paper and ink is unchanged.
I don't make it for baryta (Ilford Gold Fibre) prints, because I find it too difficult to do it really well (the paper curves under the spray, leading to drip marks on the borders) and I don't like the gloss added.