For me it came down to the fact that I'd psych myself out on tests, and even the simplest mundane tasks become more difficult. On a checkride, or bouncing around in turbulence, do I want to count tick marks or just get the number? I'll take the number. Between the Sportys E6B and the CX-2, I chose the CX-2 because of the display and the additional features. The Sportys version has a really simple LCD like the kind you would find on a 1980s calculator. The CX-2 has a much more complicated alphanumeric display and a cursor, allowing for a more dynamic menu structure and the ability to scroll through the input variables, change what you need to change and recalculate the problem if you make a mistake.
I'm a huge fan of the whiz wheel, slide rules and other old school technology - the use of which will put hair on your chest - but I'd rather just read a number off a screen and spend the time it would take to multitask flying an airplane and counting slide rule tick marks on something more productive... Like say looking out the window so I don't have a midair and DIE. :beer:
PS. Don't forget about Distance = Rate * Time. Works great for fuel burn too.