This little buddy is built well and the padding makes holding easy and stable. I think that the buttons are quite hard to push, even with adjusting, but maybe it's just my fingers.
From minor cons i would want to notice that buttons started to squeak after week of using - BUT- it's really unnoticable, especially when you train and do something else. Also it doesn't affect usability in any way.
If you have some time in work, during transporting to job, school, etc or simply struggling with guitar techniques it's a cool accessory - if not for real training, then surely for pumping some blood in fingers right before playing ;)