I've used the M27 Belgian strain twice and had good results. First was a Leffe clone, came out fairly close, with loads of spicy character and a definite pepper note. Dried the beer out very well, too, without using any sugar (1062 down to 1008). In fact it might have gone a little too far, the mouthfeel was a bit thin.
I saved about a pint of the cake after kegging that beer, and pitched it into a strong gold (OG 1074), along with a packet of T-58. It went down to 1012. Drinking that one now, and loving it - good body, complex spicy estery profile.
Now I have several carboys of cider going with M2, having heard good reviews, and am hoping that lives up to the hype.