I know we have discussed this a little before but I have been thinking more about this.
I have come to the conclusion that a rail square probably is the more useful option for the casual DIY'er or light tradesman.
MFT's are great I am sure and they offer you lots of options when it comes to setting up stop blocks, jigs etc. If you are running a small production shop like
@petermillard they are almost certainly the best option, at least to start with anyway (you might still want a square as well).
If however you are mobile in your work, or you just simply don't have a dedicated space and have to set up in your garden or garage then I think a good quality rail square is the best option. Why?
Firstly, it's super portable, it's no more difficult to transport than your tracksaw and track, takes up barely any room.
You can use it with any cutting surface, on the floor, on trestles, on a bit of insulation, even just hanging out of the boot of your car if needed.
You can use it with any size track. Big cuts or small cuts are no problem, it will work with whatever size tracks you own, great for small spaces but can do a full sheet if you have enough track length.
You can use it for any size workpiece. You can cut a full sheet in half if you have a big enough track, try setting up dogs for that on a standard MFT size table. Or going the other way it would work to do square cuts on 2x4's when framing out a deck.
It works great with offcuts. You can very quickly take an odd shape offcut and square it up ready for use. Yes and MFT can also do this, but firstly it has to fit on the MFT and you have to faff with the dogs.
I think that about covers my thoughts for now lol.