First off, at this price point you won't be getting the greatest mandolin ever crafted. However, if you are looking at dipping your toes into new territory without spending hard money - you can't really complain with what you get here.
Tuning stability is alright, you'll be tuning up semi-regularly but not so much that it'll be an annoyance. Quality for the price is very good, hardware is functional, body is strong enough to take some hard playing. I've had this about a year or two now and nothing has broken off.
Overall, for the price of checking out another stringed instrument you cant go wrong. If you're looking at using this in a professional setting I'd recommend spending a little more for something that'll hold its tuning better.