Love the idea of Shift and keeping every single email account along with other software at your fingertips. We love not having to go back and forth between tabs to look at different email accounts. Everything including all your fav extensions are right there in one place. It's great.
The team at Shift feels slow to fix certain bugs when they update versions. Typically when they put out a new version, something will not be caught up and you'll have to wait for a... glitch to be fixed. It's great when everything works, but if extensions and plugins aren't keeping up then it stalls everything.