Ray was the best. He's the best skater to have won (only Chris Fountain challenges him there imo) and his performance skill rivals Suzanne and Hayley.
Suzanne's probably next. I think she demonstrated more skating skill than Hayley and by the end of the series was absolutely sparkling on the ice.
I'd put Hayley and Kyran about equal. She's much better than him on performance but he's better on skating skill. She's still a fairly decent skater though and he did a lot with his performance skill during the series, especially considering his background.
And then, to quote Kyran, we have Gaynor Faye who won the first series... To be fair, it wasn't so competitive then and we didn't really know what to expect.