Worth the price difference is subjective. In terms of reliability and longevity, MOSFET's make solenoids seem downright crude. Unfortunately, they're expensive components, and in order to handle winching current, anywhere from 10 to 50 are required. It's a challenge and an art. We use them in our POWER-GATE Solid-State Relays and we handle up to 600 amps continuous with no heat-sinking...soon going up to 1,400 amps, no heat sinking. So yes, MOSFET's are viable, more reliable, but a more expensive option to mechanical soleniods and relays. As the technology gets more widely adopted, like most technologies, the prices will drop, eventually approaching and eclipsing costs of conventional solenoids. It'll take time.
I did measure and I can't tell if it would fit or not. If it does fit it would be with clearances of less than an inch in a couple of places but hard to tell. I called ARB but they didn't know if it would fit. Guess is no. Of course, they don't seem to know that the M12000 fits either....
email Warn customer service. They can tell you if the dimensions are the same as the M12000. One of the 9000 pound winches fits within the M12000 footprint, but most do not. I seem to remember the one you are looking at does not. I do know from install experience the M8000(with spacers), M10000, and M12000 all fit.
Regarding solenoids-they are fairly reliable, but they are also fairly cheap and easy to replace. A Warn rep was giving solenoids away as spares at Cruise Moab-you may remember-it was Steve riding with Marty.
I've had four Warn winches. Of those, three I still have all with solenoids, and Ive lost one solenoid after 9 years on one after it went swimmiing. But what? $300-400 more? The solenoid was $12.
