The hand pump gives a smooth, controlled vacuum without any sudden pressure jumps, which was my main worry. Being able to glance at the graduated scale and see exactly where I'm at makes each session way easier to track.
The graduated scale on the clear cylinder is genuinely useful, I can actually track progress week to week instead of guessing. The pump action feels smooth and the vacuum builds gradually, so it never gets uncomfortable.
The vacuum holds steady once you get the seal right, and I like being able to watch the pressure build through the clear cylinder. The pump handle takes a bit of getting used to but it's smooth enough after a few tries.