you will find in the LandSpeed religion there are two "definite" trails of thought on this,,
everyone uses suspension on the front, but, on the rear, one camp advocates "Suspension" the other camp its "Hardtail",,
a lot of factors involved, engine size, weight, power, Speed, all contribute,,
I am in the "Hardtail" camp (+200mph bike), and when this subject comes up (usually over a few beers
) the first question I ask the Suspension folks is, "have you ran hardtail at all, or for more than one event ??", 95% of the time the answer is "always" no,,
"Your Call"