I agree, repairs are fairly straightforward....BUT...Just one point...purging is easy, recharging the system with nitrogen is not.  You have to have proper equipment/tools and the nitrogen.  The dealer can do it for a couple hundred bucks IIRC.  This is where AlfaOBD becomes necessary...for DIY repairs.
I agree with 
@CaptainCJ35 ....the system is quite robust, even on the 4th gen where the only consistent problem was in sustained subzero temps.  Air suspension has been around a LONG time and is a simple, well-proven system.  I do seriously regret not having it.