The traditional method is to install at the rear as
1. The wiring and holes are better hidden.
2. Conventional perception that more light output towards the front is desirable.

You should try both locations and see which works better.

Thank you so much, Davidtay. Makes sense.
The reason I read for installing in front such that the light faces the back was that it would be more evenly distributed over both the backsplash and the countertop, plus glare would be reduced. But I guess with light rails beneath cabinets, glare would not be a problem.
I'll try both, as you suggested.

It is not strange or uncommon to install in the front, although many contractors seem to install in back by default. We installed ours in the front and the light spread much better than when installing in the back.

That's good to know, calumin. Thank you!

Don't mean to hijack this thread, but if we mount LED fixtures at the front of the cabs (current xenon fixtures are mounted at the back) how do you deal with the wires, or "plugs" that are exposed under the cabs? DH is concerned it would be a safety hazard to have exposed cords in the kitchen?