There are a lot of different neck profiles out there with different advantages and heritage. Also when it comes to combinations on the neck positions – From 1th to the 18th fret etc. Here I’ve collected an overview of the most common neck shape profiles for the electric guitar.
 
 
 
 
 
 
 

U shaped neck

Usually on thicker necks, great for players who play with their thumbs on back or side of the neck. Examples; “51 Nocaster, James Burton Telecaster.

D shaped neck

Modern shallow shape or “Modern Flat Oval”, usually with a flatter radius, found on HM style guitars.

C shaped neck

Oval C shape, comfortable shape that works well for all playing styles. Example; American Vintage “62 Stratocaster.

Hard V shaped neck

Extreme “V”, only “thumbs-over” players allowed.

Medium V shaped neck

Classic “V”, great for thumb-over-the-top blues and country players. Example; “56 Stratocaster, Jerry Donahue Telecaster.

Soft V shaped neck

Compromise ”V” room down the center for your thumb, enough of a “V” for over-the-top playing. Examples; “60 Stratocaster, SRV Stratocaster.
 

 
 
 
 
 
 
 
 
 
 
 
 
Three other factors play a major role in the feel of the neck that you may choose –

Depth, width & fretboard radius.

Depth or thickness, is the distance from the front to back. Classic “50s Fenders generally run from 22 mm – 0.870” thick at the first fret to 24.89 mm – 0.980” at the 12th. “60 – 20.83 mm – 0.820” to 24.38 mm – 0.960”. Modern necks – less tapered at 20.83 mm – 0.820” to 22.10 mm – 0.870”.

Width is measured from side to side. Usually at the nut. Vintage Fenders measure around 41.91 mm – 1.650”. American Standards are 42.86 mm – 1.6875”. Classical guitar around 50.8 mm – 2”.

Radius is the curvature of the fingerboard. The tighter the radius, the more comfortable the neck, especially when playing chords. Flatter radius allow lower action if you’re bending strings. Stock radie from the custom shop are 184.15 mm – 7.25” (Classic Relics), 241.3 mm – 9.5” (American Classic, Classic player) & 304.8 mm – 12” (Robben Ford & D’Aquisto Series guitars).