Best thing to do would be to ship some blades to us. We'd give you our 1/2 or 3/4 FIRE, and you can test them out. Unfortunately, since they are not the same thing, there's no direct comparison for FBV OR BFD cuts. It's the same premise, but we'd never guarantee that one feels exactly like the other.
Most mixed reviews of FIRE (all cuts, not just 3/4) tend to be from skaters trying a flat bottom hollow for the first time. And as anyone who has skated on flat bottom knows, they DO feel different. Folks will write in stating "I love my 1/2" Radius Ring (traditional hollow), but would love to try out a flat bottom ring." For these customers, my first response is always "If you love 1/2" RR, maybe stick with 1/2" RR, but if you're going to try something different, know it's going to feel very different when first skating on the 1/2 FIRE". Just because you love 3/4", doesn't mean you'd like the feel of a 3/4" flat bottom equivalent. Just be aware of that when trying it/them out.
Hope that helps!