We are using the 200E in our environment. We had 200D before.
We're not using the latest version of the solution, which is 6.4. I like to wait on new versions to see if it is stable before deploying it. I like to take my time and avoid headaches where possible.
I would recommend the product to other organizations. It's got great bundle options which make it a very good choice - and it's much cheaper than Cisco.