I've definitely had some success using it with Wine as well.

I've had several chances to connect to the Keen via 4G and have had very few problems. I'm using an iPhone 6s+.

I'm on the Verizon network and have been able to connect the majority of the time without issue. A couple times (maybe 1-2 out of 100 connects) I have had issues saying login failed at least 3-4 times, but then it was able to connect after re-attempting. Closing the app and restarting it also seemed to solve any login issues as well. It didn't seem like there was a specific reason that the login had failed and my home connection was up and stable at the time (my home connection is monitored).

In testing over 4G today multiple times (6-7) I have not had a single issue with connection or login now. In fact, the login process seems significantly faster than my past attempts so I'm not sure if any updates have been made but I am seeing noticeable improvements.