Clipless Shoe Types

[Micki Rider]

Hi, Everyone,

My first pair of Shimano MBS shoes cause my feet to go numb, and a friend suggested I try some Sidis. I've ordered a pair (from TE, my favorite store) although now I wonder after spending that much $ on shoes if I'll be forever relegated to SPD pedals, when I eventually want to try Speedplay pedals. Are the Sidis compatable with both SPD and Speedplay, or did I order the wrong shoes?

Thanks for your help. I've learned so much from this forum already!