Korg Mono/Poly

Hi all - I am ready to make my mono/poly have midi capability, and 
came across the MidiJack at this link:

http://www.synhouse.com/midijack.html

The only drawback that I can see is it's MONO only.  Any opinions on 
this?  What is my next best alternative (with price being the factor, 
I guess I should have said next cheapest)

Thanks in advance.

Rich