I bought one but did not use it as much as I should have until I watched the demonstration a couple years ago at the convention. Now I use it regularly and the more you use it the easier and quicker it is. The "Vacuum Test Guides" provided by Sonnax have been a big plus is its ease of use. The only drawback, if you can call it one, is that you have to clean and assemble the VB dry, vacuum test it, and them disassemble it to ream the bores, then re-clean and reassemble. But the time spent is saved in less headaches.