It can be hard to configure at first ( as is the case with all dynamic VPNs in my experience ); but once it is configured it is stable. It is easier to configure from the Web Interface ( JWEB ) and you'll find a lot of support on the forum to help you with your configuration once you get to that.
With regards to the supported platforms, I personally have it running on Windows 8 and you can find more details here :
I would advise you to contact your Juniper Rep. and see how you can get an account with Pulse Secure as that will give you access to the latest version.
Don't forget to mark my answer as a solution if it does answer your question/ solve your problem !