You won't regret it (and they're made in the UK - that still amazes me, in our post-industrial culture!).
The only odd thing is the depth guide: I find you have to add roughly 6mm to allow for the rail thickness, if you're trenching or similar. Apparently all saws of this type are the same (at least the Festool is, so I'm told),
but the centre line about which the saw tilts is precisely aligned with the bottom edge of the sacrificial rubber strip. I've put an "add 6mm" reminder on mine in Chinagraph pencil, but when you tilt the saw, it still cuts exactly to the line! This is inconsistent, but very handy: doing the boards I've just finished, I needed to put about 20 degrees undercut on the boards at the edge of the floor so they go into place nicely. No problem whatsoever - just dial it in, add a few mm depth for the extra thickness, and cut.
It's also surprisingly quiet for a brushed motor and quite lightweight. You have speed control too so you can dial it down to match whatever you're cutting - it helps minimise burning.
To be honest though, for the one-off job, I'd just make a guide with a straight-edge per that video. The fact your saw runs slowly (worm drive) is probably an advantage. Start with a new blade, or get the current one sharpened, and go at whatever speed the saw is happy cutting at. You're cross-cutting, but I'd still use a general purpose blade, as the deeper gullets mean it will clear the dust well and not overheat. It's also worth scoring the visible surface before you start the real cut, once the guide is clamped down.
Also, although this may be impractical with a Skilsaw effectively used freehand, Festool recommend a very, very slight toe-in with the TS55, so that the back edge of the saw disk scuffs the waste material, not the workpiece. It's only the thickness of a piece of paper. You might find just hand pressure anti-clockwise as you cut is enough to do it. Finally, I suggest you cut it long first by 3/4" to test your technique, before going for the real thing.
Hope it goes well,
E.
PS: on the cut depth - I forgot to say that there are
two blade diameters. Mine came with a fine cut blade, and when I bought the GP blade (40 tooth, IIRC) I found it's bigger. It's only a nuisance if you're cutting on something you don't want to dig into, say a stack of plywood (
), or trenching, but you do have to remember which one you're using, as the depth gauge will be 'wrong' otherwise. The Festool ones are all the same size, I think, but their blades are much more expensive, at least here in the UK. E.