I have carbon insert shoes but not the red cleats and no, ive never used SPD. My mtb has flat pedals.
That being said I've ridden my CX bike (with SL) through some shit and it felt great being locked into the pedals!
That's funny because I've been considering slapping my SL pedals on my mtb just for funsies. I love the feeling of being locked into the pedals and my shoes are super stiff. It would feel so good but for the obvious cons. lol
I have carbon insert shoes but not the red cleats and no, ive never used SPD. My mtb has flat pedals.
That being said I've ridden my CX bike (with SL) through some shit and it felt great being locked into the pedals!
The problem lies when needing to dab a foot. lol