So looks like Apple is up to it's old tricks of removing useful features and introducing bugs. The biggest issue we've seen so far is the removal of the ability to upgrade clients ARD version from the ARD GUI. Installation now relies on running a unix command to force the client to run a software update. Additionally, there are numerous other bugs that we have observed that are simply fixed by rebooting the client.
I haven't been impressed with Apple software QA for quite a long time., and we have taken to running our own test labs before we officially sanction an update for production. But, with automatic updates being pushed in most cases, this is still likely to create a pain point for most OS X server administrators/integrators.
Consequently, we are now seriously investigating alternatives to ARD.