It's "very similar" to the Park TS-2 which is fine - the two arms open together to accommodate different width hubs, the arm with the rim testing calipers moves up and down for different rims and the calipers move in and out for varying rim widths.
Ideally it mounts on a bench - avoid knocks to any plastic bits and it will last a lifetime.
I've built three wheels now using the bike frame as a truing stand. If I was building a wheel every month (or more) I'd buy a dedicated truing stand, but it seems a waste for the very occasional use I'd give it. If you're forever having to true your wheels, there's something wrong, IMO.
Tip: A clothes-peg clipped on to a mudguard stay makes a surprisingly good lateral gauge!