Years ago after buying my PC I wanted to try out a rotary but didn't want to spend a couple hundred bucks on a quality rotary and happened across the Harbor Freight rotary on sale for $30 and had an additional 20% off coupon so I figured I had nothing to lose.
The biggest problem is that it does not hold a constant speed. If I am running at about 1000 rpm and applying constant pressure the speed not only drops lower, but also runs up higher. It also boggs down under pressure, so if you vary pressure it varies speed. Pretty frustrating to learn on. Bought a Dewalt and it is night and day. Current HF rotary is on the garage sale shelf - hope to get $5-$10 bucks for it. VIP Special - Griot's Garage Polisher & Wax Special!
Current deal through Friday is a Griots DA, backing plate, finishing pad and Pinnacle LS for $139.99. I have one of these and it has more power to remove defects than my original PC unit. I'd be worried that the HF DA unit does not have as much power as a PC and that one needs every bit of speed setting 5-6 to get defects out.