I go through thousands of tubes annually in the shop and once had a VT1000 for simple testing. Back in 2012-13 when the modular business was booming, I used one on the secondary workbench for the intern to do simple testing on customer modules. As noted above, it's essentially a pass/fail type tester. It wasn't useful to me beyond that for a bunch of reason:
- There are no published specs about what it is actually testing for
- There are no specs on the voltages at which it tests the tubes
- There are only very vague indications of what the numbers it gives actually stand for. More importantly, these numbers do not agree with quality testers I use daily nearly 95% of the time.
I think it's a great tester for someone with little to no understanding of what a tube does and just need some indicator of quality without rolling a bunch of tubes through an amplifier.