Not wanting to be a fly in the ointment but I do want to mention that on at least some forums, and on some reviews, the Humminguru at $500 or so wasn’t seen as being "all that". For those of you with one and are happy with it, that’s great.
I did read that any US cleaner powered by a wall wart simply can’t produce the same amount of cavitation bubbles with the same amount of cleaning power that a "real" US cleaner (yes, a far more expensive device) can do. No surprise there.
I think it is a matter of setting your expectations. The reason I say this is just to throw out the question of whether the OP would be better off with a $500 vacuum cleaning system instead of the $500 Humminguru?
I mean, if you are going to be buying only one machine, which one then? Or maybe keep the Spin Clean as an adjunct to the Humminguru as others have suggested?
Much will depend on what records he has (new, lightly used, or really crudded up).
I also note that Frank Landry of "Channel 33 RPM" on YouTube had some quality control issues with the Humminguru he bought and had to manually replace some parts TWICE over a period of a few months. He said their customer service was great though, sending him out the parts with clear instructions.
I too have a Spin Clean and have had mixed results with it. Not bad but not great either. Maybe that Knosti with the better brushes would be better. So I’ve moved up to a vacuum system based on the Vinyl Vac, but by the time I bought all the things necessary to construct it (including an automatic rotating turntable), the drill bits necessary, the wood to make a platform, etc., I had invested as much a buying a Record Doctor VI, however I expect my "homemade" system to be better and last longer. Some reviewers say the Record Doctor V and VI are constructed of plasticized cardboard, so it definitely won’t stand the test of time.
One of the vacuum systems by Pro-Ject might be a better choice long term.
