[Cheesehead]

I had both, so I will try to compare both the cars. My Backdraft had a Ford 342R, the SPF has a 393cu Ford.

Weight: Backdraft is lighter, maybe the SPF has a more rigid chassis, suitable also for Big Block power.
Dimensions: the Backdraft has a 92"wheelbase, the SPF the original 90"
Handling: this has much to do with the setup of the car. I think the Backdraft handles a bit better.
The Backdraft has a more modern approach with electronic gauges. The SPF is more authentic.
Bodystyle: a previous photo's show: the bodies are different. Follow your personal taste.
Overall build quality: here the dealer makes a great difference. I think the SPF has a better overall quality
Support: both brands have a large owners group who know a lot about their cars. SPF (SCOF) has a very, very good technical library. I am not sure Backdraft has one.
Resale value: you pay more for the SPF, but the resale value is also higher.

Both cars are great. You cannot go wrong with either one. Both can be upgraded to your personal tast. I now have a SPF. For me: if you want a sixties looking car don't go for a modern style recreation of it, go for one that looks like the original. My SPF is great, it is the best present I ever bought for myself. Every drive in it makes me smile for days.
There are not many SPF's where I live. At meetings other Cobra owners look at my SPF and say: there is something different that makes your car look better than the others. I know this is because it looks more original. So, the SPF is a very good Cobra and more original and I like that.
An important factor is the dealer. Both cars can have small issues. A good dealer nearby is an important factor.

Just my 2 cents