I can't say what they have improved in the past two years, but we bought Airwave instead of Central (we were on trial).
You have to maintain it of course, but we are able to add most of our non-Aruba HPs, Comware based switches as well. Also, requires site to site connectivity, some SNMP or SNMPv3 configuration, but its not to bad.
Also, un-managing a IAP cluster takes about 15 seconds to do, and it adds back in about the same. Additionally, the complete GUI, with all options essentially mirroring what you find on the IAP itself, are present. I had found that there were glaring omissions about options just not available in Central as of my original post.