A BT-010 rear last me about 2800 miles. No burn-outs but a lot of roll-ons and wheelies. I still have the stock front after 5500 miles but will replace with a BT-012 in about 1500 miles. I am at 3 rears for 1 front.
Stock Bt56 (rear) second tire, generally gives me around 5000. Front finally gave out at about 7500 miles.... Just switched to Dunlop 208! Haven't had them long enough to compare..... I too have heard good things for touring (key word) using the Avon tires.
My stock front has 11,000 miles on it and looks good considering. The stock rear was done at 4500 miles. Replaced her with the Avon ST (AV46) and have put 6500 miles on it so far. The Avon still looks good and should hit 10,000. This tire does like to wander when exiting corners hard and braking hard but thats the trade off with any ST (Sport Tourer). And to Rocket1, 20's are Bridgestones BT20's