I have had this beard trimmer for about 18 months and am very happy with it. Compared to paying for regular beard trims, this pays itself off in a few months. It is perfect for maintaining a light to medium thickness beard. I'm not sure how effective it would be for a very thick beard.
Length settings range from 0.5mm to 10mm, so it goes up to slightly over a #3 clipper.
I get many trims out of a single charge. The removable comb is very easy to clean. The unit itself is a bit harder to clean, it does get some hair stuck inside but not too bad.