The track saws that I am describing are in fact simply a circular saw + guide rail. And cutting on the floor with foam below is exactly the way to get into it.
Proper track saws though tend to come with finer tooth blades with a thinner kerf so that they cut cleaner than a circular saw. They also retract within a kind of housing so that they're safer — only plunging down when you lean on them to make the cut.
Once you use one, you'll not go back to your circular saw unless, for example, you're trying to cut some framing lumber in place.
I have a Makita [1] which I like a lot, but my sister, wanting to save a little dosh, got a Kreg [2] and is happy with it.
Proper track saws though tend to come with finer tooth blades with a thinner kerf so that they cut cleaner than a circular saw. They also retract within a kind of housing so that they're safer — only plunging down when you lean on them to make the cut.
Once you use one, you'll not go back to your circular saw unless, for example, you're trying to cut some framing lumber in place.
I have a Makita [1] which I like a lot, but my sister, wanting to save a little dosh, got a Kreg [2] and is happy with it.
[1] https://www.amazon.com/Makita-SP6000J1-Plunge-Circular-Stack...
[2] https://www.amazon.com/Kreg-ACS-SAWBB-Plunge-Cut-replaces-AC...