I've used both.

99% of the time, I prefer to use repros.

The NOS ramps typically pull a higher price, because there are a few people who consider 'restoring' a game throwing everything and anything they can find that is NOS at it, and not actually 'restoring' anything.

I put NOS ramps in my proto CFTBL, because I figured it might have a higher value with OEM parts, and it's an exception to the rule. On my 'regular' CFTBL, I have repro ramps waiting for it.

It's nice to have a choice though.

Some less popular games, though, you just gotta find what you can. I've got a NOS wall ramp assy for my Rollergames, and I don't see this one ever being popular enough to repro - and my BSD restoration featured a partial NOS ramp set because they aren't repro'd.

If they were reproduced, I'd buy repros!