FWIW, I've had two different sets of Shimano wheels over the years. A while back I had some (I forget the exact model) that were probably the precursor to the R500s. Right now I have a set of RS20s. I've never had a problem with either. I am a light guy, so I'm not terribly hard on wheels. For around $200, how can you go wrong? They aren't the lightest or the stiffest, but they're great for the price.

If you're dead set against Shimano try some Forte Titans. Those are a comparable wheel for the price. That's what I had before the RS20s, and I'd still be happily riding them if not for a freak accident where I ran over a tool that poked a hole in my rim.