Let's see if I can explain this one from the perspective of an FFR owner who has also owned ERA,Contemporary, SPF and far too many FFR's to keep count of.
SPF, Very refined, fit and finish is top notch, bought as a roller or used as a turn key, you cannot go wrong at $38,000 for a painted roller....Frame is square tube, but do not hold that against it as the square tube vs round tube hype has been beat to death and the naysayers on both sides will say theirs is better than the others.
FFR, sold as a non turn key kit, fit and finish is left up to the individual owner/builder. Not as refined or as water tight as the SPF or ERA. Still a ton of fun to not only build, but to get in and race (I happen to have road raced several of my old FFR's). I've seen some extremely nice FFR's, and have seen some truly horrible builds that make me wonder why I bought them to tear down and rebuild. Safety factors prohibited me from doing anything but trailering some of these cars home...Some purchased less than 5 miles from my old address.......Again, fun to build and drive it your way. Downside is the attention to original body details as the current FFR body (rear end) is not as faithful to the original, even with the changes they have made to their current MKIII.5, the upside is if you wait, they will have a body splashed off Dick Smiths original 427SC coming out some time in the near future. Again, do not get caught up in the round tube vs square tube argument, as both have been engineered by their respective manufacturers to exacting safety standards. I've seen several FFR,ERA, and SPF's that have been in major accidents, and each one kept it's occupants equally as safe (similar collisions).
I have also seen some beautiful Backdrafts and would not rule them out, cannot personally comment on them further as I have yet to own one
.........
Now, of course the real question is, what do you plan to do with the car? Are you building a big block or a small block powered car? Are you looking for a nice street cruiser, or do you plan to drag race, autocross, or road race with it? Your intended use, and your realistic budget is the real deciding factor.......
Hope you find this helpful.
Sincerely,
Bill S.