I'm looking for the best hvlp gun. Transfer efficiency wise. Does anyone know of any sites or articles with a head to head type comparison? Or any preference of your own? I'm trying to narrow my search down. I'm willing to give up a bit of transfer efficiency for quality. Any and all input would be much appreciated.

Squirrel11
Gilbert's Rod and Custom

EPA says minimum 60% but variations in material, environmental conditions, technique, PSI at the gun, etc. will put the gun into a pretty wide range. I don't recall ever seeing specs from the gun companies on this nor would I trust them if I did.

Since HVLP guns do not need to be tested by SCAQMD, you likely won't find TE numbers available.
Only spray guns that are Trans-Tech or Compliant will have to prove that they are >65% efficient. They are listed on the South Coast website (http://www.aqmd.gov/home/permits/spray-equipment-transfer-efficiency)
As Chris said, a lot of the transfer efficiency will depend on type/brand of paint, inlet air pressure, environmental conditions, air cap + needle choice, etc.

Why even bother with HVLP's? RP (AKA complaint guns) give much better finish quality than any HVLP. With less volume at that.