i gotta disagree with dutret about the time aliums... maybe you just got a bad pair? i have as set on one of my bikes and another set of the atac carbons on my "nice" bike.
i can't tell the difference in release between them. and both work ever so slightly beter than the spd's i use to commute on my other two rigs.
also, my girlfriend will only use atacs now after feeling how much easier they are to get in and out of then her old spd's.
spd's definitely win the durability war though, especially the cleats.