Comfortable, compact, convenient... just to say something. I bought it 4 years ago and as I said it is one, if not the most, piece of tech gear I love. it's imperceptible and because its position is fix to your backplate and close to your back you just can feel nothing. In few words it's very very integrated allowing you a perfect trim.
The only downside I found is only two different weights available 8 lb and 10 lb.