though i love my sharpmaker other than my CQC12 it doesnt really work very well imho on EKI's, oh sure it will work but either ya have to use it as a std benchstone (in which case a std benchstone works better) or ya have to hold the knife at an odd angle to hit the bevel right, for me the best way to sharpen a EKI is with my norton hard india stone, a DMT diamond rod, and a gerber steel.
ditto with the edgepro, unless ya are gonna change the bevel; on a EKI the std stone/etc works better, same with gatco, etc.
for 99.9% of knives though the sharpmaker works great, and will do an EKI in a pinch, it just isnt the best tool for that job imho. i use mine all the time.
the edgepros too work great but i dont like clamping stuff onto blades, it will marr the finish, and its a PITA. edgepro will put one helluva edge on a std bevel knife though.
a lot depends on if ya can free hand sharpen, if ya can, no probs, if ya cant none of the systems i have seen work very well on the EKI chisel grinds, which is all the EKI's except the CQC12.
of course imho the CG is very easy to learn to sharpen but i may be in the minority on this one a lot of folks have probs with them it seems.