flax im in the same boat as you, im about to convert my MFI cabby over to FRST stuff, but after reading about MegaSquirt i am very tempted to have a go.....i am also on a budget.....
From what people say i gather MegaSquirt is supposed to be the best thing around for the price, but if you can afford more then im sure what Jano has to offer will be better, but obviously you need a deeper pocket.
Just don't forget though one of the nice things about MegaSquirt is being able to plug it into your laptop and Map it yourself, if you want to that is