I looked into building one on a samurai that i had. I did a little bit of asking around and everybody i talked to said it was really hard to tune. Ive never tried it myself, its just what ive been told.
There is a lot of good info here. I know of multiple people running a mega-squirt setups on BBFs that loom around on 460ford.com. Might be able to talk to some people that run it everyday. I looked at the projection stuff but ultimately I started collecting parts to basically swap in the 5.0 mustang mass air fuel injection setup. Parts are plentiful and fairly cheap. Best off all the mustang stuff is so popular that there are way more people using and tuning it than probably every aftermarket kit out there combined. As a matter of fact the mass flo efi stuff is based on this factory ford 5.0 technology. One thing I dont think anyone mentioned yet is there seems to be a lot more tuning involved then most people realized. Myself included. If you really dig down you will find that most aftermarket kits still need a fair amount of tuning even though they all claim you just slap it on and go. I think it is worth it, though, but I think most people get frustrated thinking that the hardest part is over when you get all the wires connected and everything bolted down. Anyone interested in learning more about the factory ford setup should check out www.fordfuelinjection.com. A lot of good info about fuel injection in general.
i am currently working on getting all the wiring in place for a megasquirt in my bronco, haven't got to mess with the computer yet though.
i chose to go with megasquirt not only because its simple and cheap, but i can tell it exactly how much fuel i want it to feed at any rpm/load, and the newer program can be used with a wideband o2, which is a major plus. im also in and out of the mountains all the time and i really like wiring too, just some wierd thing of mine i guess...