I use the Yonex MP-5 which I think is a great racket. I've demoed and hit several times with both the RDX 300 and 500MP. To me, the 300 is clearly superior. It volleys better, serves better and has more pop overall. The 500 gives a little bit more spin, but the 300 gives plenty as well. The 300 feels more maneuverable as well. The extra 1/4 inch helps as well. I've just never understood the fascination with the 500MP. It's okay but nothing special. To me, it actually feels a bit awkward. The 300 is weighted much better.