Just put a new Diablo on my 900SL this evening. I used one on my DD race bike at Snetterton in February, with snow on the ground, and held a steady 95mph around Corum at an absurd lean angle. When I got off the bike 30 secs later the tyre was stone cold but hadn't budged a mm at any time. I can't ask for more grip than that.
I'm sure BT014s are fantastic tyres as well, but I haven't tried them back to back so I can't give you a proper comparison.
Enjoy, whichever you choose!
Ali