Most risers that accept both longbow and recurve limbs are better suited for one or the other. If the riser and thus usually the limbs are wide, and the limb pad angle is rather large, recurve limbs are usually better. If the riser is narrow, and accordingly the limbs are narrower, and the limb pad angle isn't as great, longbow limbs work better, IMO.
For example, I have a Morrison Shawnee. IMO, the riser is much better designed to accept and get better performance out of longbow rather than recurve limbs. On the other hand, the Morrison Cheyenne riser gets more out of recurve limbs than longbow limbs. In the looks department, too, longbow limbs on a Shawnee riser and recurve limbs on a Cheyenne riser just look better than their counterparts. That's my experience and perception. I'm sure some would disagree with me.