I've had my E93 for almost 2 years now and when initially bought it had Michelin PS2's fitted front and rear. I have found, not only on M3's but other cars, that Michelins are a fairly soft compound along with Pirelli's as well. In the M though I've averaged about 9K miles on a set of tyres, give or take.
I am currently trying out Conti 3's on the rears and Michelins on the fronts as I have found Contis to be a bit harder wearing, though not much it has to be said, taking into account the M is a rear wheel drive car. Some may disagree with my choice but hayhoe thats choice for you!....Obviously there is a price factor to take into consideration. That said, tyres are the only things that make contact with the ground and from a safety point of view, and should not be compromised.
Bottom line, it comes down to how you drive the car, how you look after your tyres, ie bouncing them against the kerb when parking ( might be the cheaper option than having diamond cut's re-skimmed!
), potholes in roads, etc. Also included is personal choice , we've all seen them cars, (not M3's i hasten to add) with a different make of tyre on each of its four wheels. never worked that one out!