Hi Jim,
You asked for them, so here are my opinions on mounts and hinges.
Mounts - I don't use them. I don't believe in the MNH fad or gimmick, however real it might have become. However, from what I have seen from stamp lots purchased, mounts like the Showgard Mounts and Scott Mounts are probably best. Crystal Mount glue discolors over time and ruins albums. Someone has said they can also add a glaze to some stamps though I haven't seen that. The seal-in style pouches can be downright dangerous and effect the perforations. A properly chosen for size Showgard style mount seems best since they don't appear to shrink or close in on the stamps like the pouches do.
As for hinges, the situation is pathetic. Nothing at all like the Dennison's and Fold-O-Hinges of yesteryear. They're even cut sloppily, today. From what I've used of modern hinges, Prinze will peel off stamps easier than Supersafe, but the Supersafes peel more easily from pages. Both are made in Germany. There is a Dennisen hinge out of Canada, I believe ("en" rather than "on") that's junk and more like the German hinges mentioned than the original Dennisons. And I believe it's Subway Stamps that purchased the Dennison hinge making machinery and puts out a hinge called Dennis' -- or something like that -- with a kid on the package and says they are for used stamps only. Too bad that they have the equipment but not the glue formula!
Have seen 30 and 40 year old packages of Dennison and Fold-O-Hinges sell for $10-$20 per package on
ebay! I have some of these and only use them on mint stamps that have never been hinged or were lightly hinged. Anything used or with a hinge remnant or sometimes even a common never hinged stamp gets a Supersafe hinge right now.
I don't collect covers so can't give you my input, there.