Robrenz, I have a 0-250Vac 2kVA Mastech and it works very well. I put some serious loads on it (4 or 5A @ 120V) and it held up without fuzz.
I agree with your comment below regarding the cheap switches, fuses, etc, although the unit has a scale on top and a cheap voltmeter in the front. I simply bought a 15A extension cord, cut in half, soldered the round connectors to the posts and isolated everything. You can see it in action in
this post and detailed pictures are below.
Is it a Staco? No, but it did not cost me an arm and a leg and serves the purpose.
I would say that a variac is absolutely wonderful for someone that has to deal with mains voltages. I have my share of blown up things that not only cost a lot of money to fix but also were very close to end up badly.