$29 for Cab Lab,and a few minutes to convert them. It's a cheap price to pay to try it out. I did, and I prefer the UR's, as I do with almost all of the cabs.
Will the difference between the UR's stand out dramatically in a live band mix? Probably not....
Will they sound better on cheap-o deap-o speakers? Probably not.....
Do they sound better with good monitors, earphones, or wedges? Yeah, they do......
Do they sound better in a studio or rehearsal space? Yeah, they do - to me, at least.
Do they make you play differently, when you are in a space that you can distinguish the difference? Yeah, they do for me.