FYI - Electronics like ASA's CX-2 are usable on FAA Written and Practical examinations. They have to be capable of wiping their own stored memory but other than that not much is said about using them as opposed to the E6. But from a practical standpoint as a student I still use the E6B and I probably will continue to do so until I'm in to or past my Comm. You can actually do most flight computations almost twice as fast on the E6 as you can on the CX-2.

I own a CX-2 and I use it for weight and balance (Started doing that after I became comfortable with the mathematics behind it) and other preflight activities (Finding altitudes etc.) but I leave it in the flight bag while actually flying and use the good ole' E6.