If you've made your wooden track the "traditional" way, you will have trimmed the edge with the saw, in exactly the same way you do it with the rubber strip on a track saw. So it *ought* to take care of tearout in the same way too (as long as the surface of the track is flat and meets the stock cleanly).
There are two significant differences that I can see, but both of them only matter if you need to work in a particular way:
1. You have to apply some sideways pressure to keep the saw running against the wooden rail. That might be irrelelvant, or it might be a confounded nuisance, depending on how you work.
2. You can't cut bevels accurately with a normal saw running against a wooden rail. This is because the pivot point of the tilting blade is (usually) arranged to be either on the baseplate of the saw, or some point above it. So the distance from the wooden rail changes as you tilt the saw. This doesn't happen with a proper rail saw, as the pivot point is supposed to be set to the exact point where blade, rubber strip and stock all meet each other. So it *should* be just as accurate cutting a bevel as a squared-off cut. The other issue with the wooden fence is repeatability - try to make a bevel cut and you risk wrecking your wooden rail (the blade moves towards the opposite side, usually). And if you're a Makita SP6000 owner, that hooks onto the rail for bevels, as an extra safety feature.
3. (I know, I said "two"!): you'd have to find the right depth for scoring cuts yourself. That's not to say it can't be done, but it would be awkward. I do like the push-button feature, but it's not infallible. As I mentioned, the Makita is supposed to use 165mm blades, although you can use the 160 (Festool) size, but that messes up the scoring cut feature. Simplest thing is to drop the blade onto the workpiece, then add 1.5mm, so it's not that hard, but it is another thing to think about. Yes, you can do that with a wooden rail, too, but it's easier with a track saw.
4. (I know...): Track saws are set up to plunge nicely and have really low-friction rails. This makes them safer (probably), and it lets you do things that are otherwise hard, such as cutting notches neatly. I haven't yet tried to do bowl openings in worktops with a rail (what the plunge feature was originally intended for), but it should be pretty good and a lot nicer than a smoking jigsaw with a glowing blade! Generally, too, I like being able to concentrate on the actual cut and not worry about how hard (or where) I'm pushing the saw.
Obviously you get 90% of tracksaw functionality with a wooden fence/rail, but the more I use my tracksaw, the more I appreciate the easy setup and use, and the ease of getting accurate results.
Next purchase is an MFT, from Axminster probably. Again, I'm sure you could use a wooden rail, but for me, ease of use wins out.
I really don't miss my old circular saw. I gave it away, actually.
E.
