I prefer round mag wheels because I can remove them before putting the gun in case eliminating excess pressure on the parallax featureUsed BOTH with great success and IMO the determining factor is IF or NOT you require the fitted scope on rifle to fit in a carry case being a storage or case used during a shoot
A BIG "Why For" I've always used ECCENTRIC or NAUTILUS profile wheels as they can be made compact with rotation to fit in cases as if the wheel is not even there.
A BIG round wheel .. magnetic mounting hub 100%