I've got a 28 ga Repro and a 28 AyA #4 DeLuxe (boxlock). I agree with most of the comments above, especially the stock fit on the Repro. I love the gun, but the stock is way too short. I use a strap on leather pad stuffed with carpet backing to add an inch.
An advantage for the AyA is that you'll likely be able to get longer barrels if that's what you want.
You'll be able to find a used AyA for a lot less than a used Repro. You should be able to find a new AyA #2 (sidelock) for similar $ to a good Repro. I have a #2 in 20ga and love it. Would like to pick one up in 28ga some day.
No question that if properly bought and cared for, the Repro will hold it's value.
BTW, I like both my guns a lot. I can't comment on the RBL as I have no personal experience. Good luck.
