The Blockleys are much better than the Avons with more grip and more progressive breakaway. No down sides as far as I'm concerned though some people reckon they are less good in the wet than the Avons - my feeling is that they are actually every bit as good in the wet but it is just a bigger step down from their performance in the dry than you get with the Avons. Not much difference in price the last time I looked either.
+1 Been using Blockleys for a couple of months now , including trackdays and I think they are much better than the Avons
