Respacing a rear wheel

Folks,

I have a question about converting a 130mm Ultegra hub for use on a bike
that's spaced to 135 mm. I know you can do it by adding a 5mm spacer and
redishing the wheel, but once that's done, how does the wheel compare to a
wheel originally built on a 135 mm hub in terms of strength?

Thanks,

Trent