I ran 116 frames through mine yesterday. I love it and I could not run as many hives as I do by myself without some type of uncapping solution.
It is not perfect. I would say there are possibly two negatives: (1) I can probably do a better job of uncapping with my knife and scratcher. But only nominally. And if you want to pull out the scratcher after running it through the SHF uncapper, you could equalize that and still be world's faster; and (2) the SHF damages the cells more than cleanly cutting the cappings off with your knife. The bees build it back fairly quickly and seemingly easily. However, I don't know what type of "extra" work I am giving my bees in rebuilding the cells that my knife would prevent.
Advantages: (1) Speed, Speed, Speed. Absolutely no comparison. Each frame 10 to 15 seconds and into the extractor. It used to be that my uncapping could not keep up with my 18 frame extractor. Now my extractor cannot keep up with my uncapping. (2) Eliminates mounds of cappings to strain. After 116 frames yesterday, I was left with maybe a pound or two of cappings. Could have gathered it all in both hands. If you want wax to render for candles, then you might not want the SHF. I hope to never have to drain cappings again. (3) Wrists. The uncapping knife was brutal on my wrists and arms. I found it very hard to make it through 150+ frames in a single session. You can work the SHF literally all day.
BTW, I am the fat guy in the red shirt on the youtube video. Simple Harmony Farms Uncapper Product Review. 16:54. Sorry I can't access the link from my work computer.