My review is based on versions up to 2.5.5, which I'm currently using.
I've used this app for 7-8 months and it's been more reliable (most of the time) than other apps I tried which require you to scan a QR code or enter a number code shown on the other device.
The first couple versions were buggy and sometimes wouldn't see my phone at all. It's been better lately, but still often disconnects and requires re-opening HS on the phone/computer/both and/or re-plugging the USB cable to the phone.
The earlier versions had a cleaner GUI, with just transfer abilities.
Now they've added something called "idea pills," which I suspect is useless to at least 90% of the people using HS, and I have no need for.
20 minutes ago I connected my phone, opened HS and was notified of an update. I let it download but to install it wanted access to my camera, which it has never needed before. The message said "Allows the app to take pictures and video with the camera. This permission allows the app to use the camera at any time without your confirmation."
Maybe that's a standard message displayed when any app needs to access the DCIM>Camera folder. But it's never needed it before to transfer photos or video to/from my Mac. And you must allow it in order to install, so be sure to immediately disable it in Settings>Apps>Handshaker>Permissions.
A previous version requested access to the phone and I disabled that, too.
I just checked the dev's website and the latest version has begun using QR codes. :-(