This is a great product for the places you need it. It doesn't offer any real features other than a decent, responsive tuner with adjustment between 430Hz-449Hz. Just does the basic job well.
I mark the quality down to 4/5 simply because the switch is really only to be used by feet and it's a fairly firm press. It also needs/wants to be evenly pressed; if you put pressure on one side it doesn't feel good. Doesn't really lend itself to being pressed by fingers, but using your palm is easy enough. The recessed screen has a thin plastic sheet and if that took the force of the press, I think it would break it. It might not, but I'm going to risk it. If your shoes have a specific knobbly tread, it might slip in and break it.
Otherwise everything else is great. Really, really good. Bright display, big enough and clear enough for most people. Case, powder coated aluminium or some very firm material. Footswitch is a solid aluminium barrel. Jacks are decent. 9v jack is quality. The assembly/build feels quality. The included precut 3M double lock is a nice touch. Even the little box it comes in is good.
If you want a tiny tuner, this is a great product at a good price. My only complaint about the screen durability and the firmness comes from the fact I wanted it for a little desktop pedalboard on a laptop stand. A little awkward to use in that specific situation.