ah, things are not always as they appear, if the subway tile is larger they have to put them on individually. most of the painted glass appears to be on a backing. I understand some now allow you to just peel and stick. Then there is the price of redoing. some people believe subway is about to go out. are you gonna want to keep up with the joneses? So this time you really do have to ask the expert

Interesting question, kmcnolty, and not easy to answer. It
depends on your contractor’s capabilities and the backsplash itself. Subway
tiles are standard and can be installed by virtually any kitchen contractor.
Back-painted glass is typically installed by a contractor who knows how to work
with the material, will take careful on-site measurements, and order the glass
to size with all the required cut-outs for the electrical outlets, etc.

The material cost would most likely be comparable, but
installation and procurement of back-painted glass could require a specialized
contractor, especially if custom sizes are required.

A long-term benefit of a
back-painted glass backsplash, however, is ease of maintenance (no grout
lines), and a much greater color palette, including just about any custom color
you choose.

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and we live and learn again, splendid!