Well... put me down as one who probably prefers the 11.5 x 4 but it is close. Before going with a Saito .72 on my Dazzler, I ran a .46FX and alternated between the 11.5 x 4 and the 12.25 x 3.75 (whew, not much clearance).

The 11.5" definitely spools faster and many times gave better results over all. Part of it would depend on engine performance related to weather conditions - winter or summer.

If I could only have 1, I would take the 11.5

Photo (pre-APC)