I favour skinny necks and have recently bought an SB14, and also have some Fenders with Jazz neck profiles (Power Jazz Bass Special and Precision Lyte). Plus a selection of assorted JapCrap with Jazz type profiles, but not an Ibanez.
I am not sure how to measure it but on a comparative basis the width of the necks are exactly the same, but the SB14 is slightly deeper than the Fender Jazz necks. In hand the feel is nearer to the slightly wider and deeper Westone necks, although a tad shallower than these. Not as deep as some P-Bass necks I have tried, though. I find it extremely comfy, I have to say. Also the way it hangs is different - the smaller headstock and general body configuration make it a couple of inches shorter than the Fender Precision style bodies I have, which I find makes it slightly easier to play - the balance is somehow better like this. Sound wise there is a world of difference.