The main weekness is the size of the paint pot. Its quite big so rather wasteful when you want to do touch up or rectification after your main coat.
I don't think they smaller pots or a gravity version. As it is a proprietory system you can't fit other guns to it.
Other than that they are quite good. They make less noise than a normal compressor. Also doing HVLP with a normal compressor requires quite an expensive one, say 3hp.
True HVLP will likely need more that 3hp, that will put out around 9-10cfm FAD where most HVLP guns need more than that, like 15cfm not untypical. Except maybe small guns.
Never used one of these but was under the impression that the air is relatively hot, having being beaten about by the turbine.
tbh for that money I'd go for a compressor and conventional gun. Could get a decent comp and gun, and the comp will have so many uses longer term. Also means you can use different guns, like small touch-up gun, full-size etc.
But the lower overspray of HVLP must be nice ...