I have both, the SPDs seem more solid, i highly doubt the XC 8 will get half of the mileage of the shimanos, these things are indestructible. That said the ATACs are lighter and harder to unclip (And clip too, sadly). If price is a deciding factor SPD are way cheaper and the cleats too.
Ultimately I'll change to ATACs because I like the floatiness and the secure feel, tough I only unclipped the SPD using some 10 year old pedals & cleats, and because they look better in my bikes
I have both, the SPDs seem more solid, i highly doubt the XC 8 will get half of the mileage of the shimanos, these things are indestructible. That said the ATACs are lighter and harder to unclip (And clip too, sadly). If price is a deciding factor SPD are way cheaper and the cleats too.
Ultimately I'll change to ATACs because I like the floatiness and the secure feel, tough I only unclipped the SPD using some 10 year old pedals & cleats, and because they look better in my bikes