Likewise, the SWEL motorfocus has worked well for me.
The robofocus can talk to a computer to autofocus. The SW at 1/4 the price is just a remote controlled motorized focuser with variable speed.
I can run my Vixen R&P focuser all the way out and back in again in what seems to be about a minute or so. I haven't timed it. Most of my eyepieces are pretty close to parfocal so I don't have to change the focus by a long distance.
I can also set it to very slow and fine focus using magnified (16x) live view. It's designed for the Skywatcher focusers but comes with a few attachment bits that allow adaption to various focusers such as M Vixen VC200L focuser.
Battery is a 9V transistor. I use the motor focus a lot and I get long battery life. But I always keep a spare battery in my eyepiece case.
If you want a camera control program like Maxim to focus for you and refocus during the imaging run, then the robofocus might be the way to go. Otherwise, the SWEL works well.
Joe