I've been using the Biketek ones all season and was previously happy, especially for the money. The rear however went up in smoke yesterday at Cadwell, the resistance wire burnt out midway through the loop and was burning through the tyre jacket. Luckily I was stood with the bike when it went, just returned from lunch when I noticed plumes of smoke coming from the rear of my bike. Mark must be pissing himself as its the second time this year I've nearly torched the Gixer!
Maybe the fact that they had been on so long without the thermostat cutting them in and out was to blame. Under normal conditions they reach temperature in 20 mins or so and keep cutting in and out to maintain temp, yesterday it was fookin freezing, we were outside with a cold breeze meaning they were heating full on for an hour or two taking into account lunch, if that actually was the cause rather than a fault then they are not really designed up to spec if they cant handle constant running whilst on the tyre.
Not sure what im going to buy next but the Diamond ones are looking likely for next year.