I've never been brave enough to mix and match! haha!
I honestly picked the T30 because I preferred the look of the tread pattern but also the reviews it was getting.
Chris
Funnily enough i don't remember ever having tyres that were paired before in years of riding?
I've read reviews before where one has been good but the other not so good so i've always bought front at back at different times.
The T30 was the most decent tyre available when i had a puncture one day, and i got a bit mugged off when buying it but had no choice although i'm glad i bought it as i've found it good in all weathers, and the front BT023 has a deeper tread than normal which i really like as well.