I used 'em once on a 748 at Oulton Park. Thought they were great and would have no hesitation in using 'em again. Just as good as 207's on the track. I've no experience of 'em on the road and can't comment on life/mileage
I've just been having a look in the MCN tyre test which should help a bit as well. They have a few sets of the Avon tryes in test there, I'll probably end up going with what I know but you never know......
Never used 207's but my experiences with the previous Avon range on my 750ss as follows: AV39/40Supersport - excellent for thrashing around, highly recommended. Great for grip - rubbish life, knackered the rear in less than 900mls - (on a 750ss remember!) AV35/36 (the hardest of the 3 versions in the range) fitted in the hope of longer life. Didn't like them - very insecure feeling when cold, even warm the front seemed too hard and rather skittery. still on the bike when sold but I reckon the rear would have lasted about 3000mls. Probably the best combination would have been AV39Supersport front with a std AV40 rear. For reference, I reckon the BT010 was better as an all-round tyre ( the rears did ~2,000/2,500mls BTW) but for track days/ 'thrashing' I did like the AV39/40Supersport. Dion Oh yes and they are cheap!
forget the Azaro's or 207's ..... i've just put some Supercorsa's on my Race bike, and the grip and feel is phenomenal. Doubt they will last very long though.