I think I have to agree with Jonathan, really going in to the details and doing a proper A/B comparison will most likely show Mafell is on average just a little bit better per machine. Maybe that is because there are a smaller company and they don't try to fit as much as possible into the overall system as Festool does.
Ever since I got the Mafell KS300 I fell in love with that machine. It is hard to explain until you've used it but that machine is an A+ in engineering. It is hard to overrate that machine, all those possibilities in one sys 4, that is brilliant engineering.To be honest, I'm expecting I will probably replace my TS55 with it's Mafell counterpart, instead of getting the TS55R from all I've read and my experience with the small KS300.
In the end, if you stick with Festool you won't miss Mafell for a second. Festool's system works most of the time and they simply make excellent tools. I do think though every Festool user will be pleasantly surprised when using a Mafell. Maybe not enough to take the jump as it is not only the machines qualities that play part in deciding, but still.
Btw, I don't know how pricing is in the US but over here Mafell and Festool are sort of in the same price range. At least the plunge saws and routers are, Mafell's jigsaw really is something special so it fits that it is a bit more expensive than Festool's.
I know this is the Festool owners group but still I'm a bit surprised the love for Mafell isn't a bit bigger. For me, between those two brands I can find just about all the woodworking hand tools I need. My ideal line up would probably be 65% Festool and 25% Mafell and the odd 10% for other brands.