Regarding version 2.3 being more stable than 2.2 - how does one substantiate that? Cisco seems to claim that ISE 2.2 is the safe harbour version and by the sheer number of patches released it would stand to reason that 2.2 is more mature than 2.3 (patch 3 only). In my opinion the answer is always "it depends". It depends what you're using ISE for. I mostly use it for Guest portals and TACACS, and 802.1X - in that instance I am happier with 2.3 because there are feature improvements for Guest that I need. But Cisco have also changed some underlying plumbing in ISE that seems to make it feel a bit shaky and instable at times. I love this product ... when it works. When it works and doesn't give issues on the GUI (which can be flakey as hell) then it's a joy to behold.
We still maintain our ACS 5.4 and that is one rock solid product. I don't get the same vibe from ISE. ISE is a house of cards built on flaky Java held together with spit and a bit of polish. The marketing hype around ISE is astonishing - ISE will save the universe. Just don't look too closely. And heaven forbid we should ever get access to the underlying OS - I think Cisco don't want us to get to the Linux CLI to see the mess they have created there.
