First, text is buggy when at an extreme size: [1][2]
To view it properly I have to resize or slightly move my canvas and it somehow "refreshes" the view.
Second, there is a huge lack of support and little to no tutorials on Sketch. It's also hard to Google any problems because it's called... Sketch.
I find it ridiculous I have to shell another $50 / $80 for a new version. Just give me an upgrade for $25.
Also, for any iOS designers, I highly suggest buying Sketch mirror: [3]
You can preview your designs live on your iOS device and move through different screens, live, while you design. This, and then using LiveReload to code mockups is super efficient and fun.
[1] http://cl.ly/image/0g3y1w3i3Y3m
[2] http://cl.ly/image/3z3k0x2J151s
[3] https://itunes.apple.com/us/app/sketch-mirror/id677296955?mt...