I have a Fuji Q4 and a compressor driven HVLP system. The Fuji is quite capable of producing a good finish and it has some advantages and disadvantages compared to the compressor driven HVLP system that provides 10cfm @ 90psi. The Fuji system is definitely cheaper and way easier to use.
As a note I only spray water borne coatings (Target and General).
The Fuji does well with dye, shellac, and clear coats but is slow applying pigmented coats. You can apply pigmented coatings with the Fuji, it just takes longer. On small projects or touch ups it is a good solution. It is recommended that you dilute pigmented coats 10% with distilled water but I really don't like doing that as you get sags and runs. With 9cfm @ maybe 10psi at the pump end (lower by the time it gets to the gun) it really needs more pressure to push heavier paint out. I do like the Fuji for location work, it's easy to transport and set up. I have not compared system to system but I don't think the Fuji system produces any less over spray than my compressor driven HVLP system.
I really like the Fuji system, but I wouldn't trade it for a compressor driven HVLP system.