We've also been working on ML collaboration at https://www.tinymind.com. In addition to training models collaboratively, we have free, hosted Jupyter notebooks for both Python 2 and 3 with popular ML frameworks that you may want to check out :)
Interesting. I like the simple design/interface you've put on top of the various ML engines, including how to tweak them. Overall approach reminds me a bit of Digital Ocean's friendly UI for servers/hosting.
Haven't tried the collab features yet.