I use JMI focuser's, and other JMI accessories on my scopes. I am a big fan of JMI products, as most of their products that I use are great, but some do have limitations, as they are a compromise.
I particularly like their focuser's and have had a few of them, although I use their top of the line Event Horizon focuser's. To me, the real advantage of the JMI focuser is the discreet motor that they have. .
As for the Motofocus that you attach to your current focuser. In this regard, I am inclined to agree that they are not really that great, as they are a compromise and have limitations, which is why I went for the full focuser, although these are not cheap, but they are fantastic, in my view. I use JMI Focuser as I am only a visual observer and don't need the computer control features of the Moonlite focusers.
On my Event Horizon focuser hand control, there is a slide switch that switches between slow speed and high speed, and I have always found the high speed to be more than adequate. See picture at
http://www.jimsmobile.com/images/ev_2cm.jpg or here
http://www.jimsmobile.com/images/ev_2nm.jpg
I rarely have to disengage the motor to focus, however, I do use parfocal eyepieces anyway.
Cheers Pete