No experience with the Holub device. But from looking at the manufacturer's website, it appears to be a straight-forward design that is almost too simple to not work correctly. If I only loaded one caliber that I needed to trim, it is certainly something that would attract my interest.
But, I load several calibers that I need to trim, so when I add up the cost of buying three or four Holub "world's cheapest trimmer", it ceases to be so cheap and I will, in fact, have actually spent more that if I had just gone out and bought a Forster trimmer (or its equivalent) in the first place.
And that was the calculus in 1992 when I decided to skip "cartridge-specific" trimming solutions and bought a lathe-type trimmer. In my case it was a Forster and it is still running perfectly fine trimming brass. I keep toying with the idea of getting the adapter for a drill, but since I usually trim brass in batches of 50 or 100, but the time my hand gets tired spinning the cutter, I'm done and I decide I'd rather have that money in my retirement savings account.
After all, there's no point going into retirement looking at dinner choices of Nine Lives versus Fancy Feast.