After 16 years with TUsa liberators I want to replace my fins, espec when I felt (though I am in excellent shape and an avid swimmer/runner) I had trouble keeing up with a buddy on a recent trip (?)... The Mares Volo power came highly recommended. The foot part on a sz (S) was borderline too big - I am not interested in split fins though the sales person at the store tried promote them - any recommendations? I dive mostly in warm water but occ cold, and love having booties wherever I am... TX !