Ultrasonic LP Cleaning vs. “Thread Type” Cleaning (Keith Monks/Loricraft/etc.)

I thought long and hard about a US machine and decided against purchasing because of all the potential issues and "work" involved, at least as I see it. I would worry about US actually damaging LPs, as rightly or wrongly claimed by some others. One wants to avoid that, so what frequency for what amount of time is really harmless? What amount of heating is harmless to an LP? Can you use detergents in the bath water? Some do; some don’t. The effluent from my VPI HW17 is filthy, which makes me think I would want to change the US bath water very frequently and/or filter it via an external circulation. When all is said and done I decided to stay with the HW17, which by the way never overheats. I also use Walker Audio enzymes for really dirty LPs and combine that with a distilled water rinse using my VPI. This is purely to illustrate my own thought process and not to say that anyone else’s choice is "wrong". I also had an opportunity to purchase a string type Loricroft cleaner and was put off by the maintenance issues as described to me by a Loricroft owner. I don’t see why it would necessarily be superior to the HW17, and the HW17 presents fewer headaches. I clean my LPs in my basement workshop, well away from either of my two systems, and don’t care a fig about the noise from the HW17.

The Keith Monks is the original RCM. Used by Better-Records, BBC, Library of Congress, etc., etc.
After decades of refinement, the KM RCMs no longer use the maintenance heavy string method. The nozzle vacuums off the dirt with a medical grade German pump. The KM fluid is also special.
The fluid is easily applied and quickly brushed in. The whitish surfactant is seen. The arm is placed on the label and automatically travels one grove at a time as the nozzle vacuums up all the dirty fluid. This takes a bit over a minute a side. Quick and complete.
As opposed to several minutes for the US machines and the records sitting in the dirty water.

@mglik - I think the maintenance and care of the "traditional" Monks is overstated. When I got mine, used, I knew it was not performing as it should and had it rebuilt by the guy who does the institutional work for Monks based out of NY. He also showed me how to operate it properly and we made a few tweaks- he repositioned the "arm rest" and I added silicon washers wherever there is metal to metal contact on a screw. (Some of the old Monks show rust- frightening). Once you get the hang of it, it’s relatively easy to adjust and maintain.
I don’t use the fluid applicator head since I use a variety of fluids and I found that the dispenser flings fluid beyond the platter-- I keep a microfiber towel handy to wipe the surface as it is running, and once done, use some canned air to get water out of any crevasses, empty the waste jar, cut off the "used" thread that has been sent to the waste jar, etc. The machine wipes down easily and threading the bobbin, while not easy, is something that an owner can do with a little time and trouble- it basically involves taking the nozzle off and re-threading the "string" through the arm tube using a little rubber pipe that then allows the vacuum to pull it back through to the waste jar. You can clean a lot of records with one bobbin of the special thread.

Some of the machines may have been abused (commonly, too much waste water without emptying the jar will cause water to flow back to the diaphragm of the pump and then the diaphragm has to be replaced, if not worse). Even with a rebuild, mine came it at less than retail for a brand new Omni. The older models can be brought back to life at some cost. I would recommend that anyone buying an older Monks have it checked by someone who knows the machine. It was an ingenious sort of Rube Goldberg affair when it was first made, and has the quirkiness of a British vintage car, sans the Lucas Prince of Darkness issues.

There is a huge variance in US cleaning machines. Your question is rather like asking if a car is faster than a bike.

As @whart has noted, US results depend on frequency, power, temperature, spacing, surfactant, and rinse. It’s only when you get careful with all of the above that your results approach optimal.

The first question to ask is how much you can trust your US bath to meet spec. If it’s medical equipment from Germany, you can trust it a bit more than flimsy-consumer easy-to-use from anywhere.

There are threads on this topic which you might want to examine. A high class expert on cleaning technology, whose handle escapes me, contributed to one thread and refined my own cleaning process, for which I am considerably grateful.

I use an Elma US machine from Germany, and doubt very much that my records are less clean than anybody's.

I've been using the KM Prodigy threadless machine for several months, came from a VPI16.5 and find it quick, quiet (relatively speaking) and cleans better than the VPI. Yes US may clean deeper but are not as simple as this machine is. YMMV