It's hard for me to give a fully accurate comparison as this is my first bike and i have only ever had the siracs' and bt45 to compare.

The sirac's did bi 11.5k miles before i replaced them but they would have been legal for a few thousand miles more yet. Generally i was extremely impressed with them never had any grip problems wet or dry (commuting over the winter/spring months). My only complaint, which may be due to them being somewhat square (as oposed to the heavy tred) was they really cought on overbanding or the side of speed humps. They're

I was very happy with the siracs them but chose to try different tyres so i could learn to appreciate the differences they offered.

I've done about 3k miles on the BT45's so far and while their dry grip seems ok (as you'd expect) i've not been as impressed with their wet grip, i've had a lot more moments where they seem to have started to struggle compared with the siracs. They also cause the speed to read about 3% higher than on the Siracs. I've not noticed any noticable difference in vibration, road noise or fuel economy (after allowing for the fact the trip meter reads 3% higher than before - 188.5 vs 183.4 miles for the same trip)

Honestly the only benefit i have noticed over my squared off siracs is they are less afected by rough road surfaces, at the expense of wet grip. It's too early to compare tyre life yet. If I wern't planning to try the touraces tyres next time round i'd be going for the Siracs' again for my next set, especialy as i'll be riding them through the winter