We used Aquamix Gold sealer when our glass mosaic backsplash was installed. I think it was rated for 15 years? Still looks good as does the glass tile.

It wasn't available when we did our kitchen reno, but it we were doing the backsplash today, we'd probably have them use TEC XT grout, which is stain, crack, mildew resistant (more so than their regular grout).

Our backslpash is a combo of crackle glass and slate. We sealed everything shortly after install last July. Currently everything looks as good as the day it was installed. Haven't come across anything that was difficult to wipe off or clean. I should say though that we have a sheet of stainless behind the range. I cook every single day and most of the time quite messily so the stainless has been awesome and easy to clean in that area. Here's a close up pic of our backsplash...it may not be for everyone but I just love it. I wanted all slate...hubby wanted glass so this was a perfect compromise! This was right after install and all the grout wasn't cleaned off the slate yet. I just love all the different colors in the slate!

Yeah, behind the range is probably the area of most concern. We will have a window behind the range, so I'm not sure how well a sheet backsplash would work there.