Reading this thread got me moving. My kicker is a tiller model and it is a pain to have to go to the back to set the throttle. I have an EZsteer and with throttle control could run from the helm.
I looked into both the Controlking and the TrollMaster. The TrollMaster Pro II for a merc is $245 plus shipping. Reading comments on the web, the trollmaster appears to be a bit more up to date. It "looks" better with the LCD display for throttle setting, but that may be all flash.
I took the plunge and ordered one. Shipping is supposed to be around $22.
I'll have more comments after I receive it and install it. I'm looking forward to being able to adjust trolling speed from the helm.