I can't believe I missed this thread the first time around.
I've got some Mach 1 models as well. The first was a Testors die-cast in pewter, and like Rex said, it's OK and more of a blend of '71-'72 & '73 things which look a little goofy to those of us who know the differences.
I received a Sun-Star 1/18 scale model a few years ago as a Secret Santa gift. It's REALLY nice, too (in front of the monitor, with a Testors 1/25th to the left).
I think the only thing I don't really care for with the pre-painted die-cast kits is that they always have the stripes, spoilers, and every possible thing already added to the kits, and you can't remove anything without having to modify and/or repaint (which doesn't always go well, depending on the thing you need to change).
My wife snagged me a Danbury Mint Boss 351, which as Rex pointed out, is a very quality kit. It came already built, but it's all there and pretty much dead-on.
The ones I'm looking forward the most to build are the Doyusha "Vanishing Mach 1" kit(s). There's a 1/12th as well as a 1/24th in this one.
I also have several of the MPC and/or AMT '71 Mach 1 and '71 Boss 351 kits, which are just like the Testors kits, with the '73 front bumper and a blend of the '71-'72 & '73 grille (think '71-'72 grille with '73 headlight doors).
My plan is to build one kit as my '71 would've come from the factory, one as it was when I bought it, one all finished as it sits today, and another as part of a garage diorama with it in the process of being restored. The 1/12th will be built as the car currently sits - I scored some 1/12th Cragar S/Ss and some other goodies to make it work.
Oh, almost forgot - I have some Mach 1 funny car kits as well. My wife found Bounty Hunter and Hot Rod Magazine kits at Hobby Lobby one day. Apparently, there are a bunch of those kits: Blue Max, Parnelli Jones, and Shirley Muldowney, and those kits could also be used to make tributes of some of the other funny cars out there as well just by changing decals and looking close at the old pictures.