We've actually seen that with higher pin counts—like 36 or 42—teh speed needs to be dropped a level or two, otherwise it tends to drag a bit on denser skin, but that's just the nature of having that many needles working at once.
Most buyers we deal with are running these in salons or clinics for hair restoration and acne scarring, and the 5 adjustable speeds give them enough range to switch between delicate facial work and tougher scalp areas without swapping units.
It runs at 5V and 1000mA out of box, so you can basically use it anywhere with the universal 100-240V adapter, which means no votage headaches when traveling. Needle options go form 1-pin for precision spot treatments up to 42-pin for broader coverage—there's also nano needles (usually 2-4 weeks on those, depending on stock).
The body is medical-grade PC+ABS in white and red, nothing fancy, but it holds up well in high-turnover setting; you'd be surprised how much abuse these take before showing wear (pretty much the only thing that goes is the needle cartridges). What it's not great for is heavy-duty stretch mark work on very lax skin—you'd want something with more power and heft for that.
A detail most people don't ask but should: the ergonomic grip has a slight curve that makes it much easier to control over long sessions spent doing hair lines or jawlines. Anyway, we typically keep these in stock, around 50 units or so, but check lead time if you need more than that at once.