I have a TV10D/U contract built for the Navy. It is a great tester, built like a brick $#!thouse. It is basically an upscale model of the very popular TV-7. The TV-10 is not a very well known tube tester, because there were far fewer of them made, relative to the TV-7 and other testers.
The TV-10 uses the mutual transconductance as the measure for tube quality. IMO, the most reliable method known for assessing tube quality. I like the TV-10 better than the TV-7 because it reads the mutual transconductance directly on the meter in micromhos while the TV-7 only reads a relative number on it's meter.
It is fairly easy to use as long as you understand the various controls, can read the tube charts and pay attention to the settings. I would suggest getting the tube charts in a PDF, print and bind/staple the pages. This will save wear and tear on the roll chart and ensure the latest settings for more modern tubes. IMO it is great for BH kit, especially the DHT's.
Hope this helps,
Geary