JLG,
the brand I used last was a Huanyang 5hp VFD for a gear drive drill press..it's been going strong for about 4yrs now, I had to get programming help from the manufacturer,they have an interpreter that will return your email if you need it,they were of much help in getting it going..You have to enter in motor information and what terminals you want it to read for off/on and speeds,its not too hard if you read the manual that comes with it. Most of them work with a common pin that you short to one of three other pins with a switch or switches to select speeds or use the keypad. They all pretty much work the same,just some quirky differences but for the most part they are pretty easy to use. I have used the older Magnetek and the newer very compact Hitachi VFDs and they are top of the line for my customer machine jobs. Once you work with one of these you won't be using anything else. All you need is a 2000ohm variable resistor to change speeds,or just use the internal keypad to stop/start it right from the keypad.You can also wire it to turn on/off with a simple toggle switch,or separate lightswitch if you want. For a 5hp on eBay they are at $198 with free shipping. One thing I would recommend is to unplug it when not using it to limit spikes and surges from taking out the computer in them..I unplug mine whenever Im done with it..limits exposure to the powerline surges..FWIW best of luck