not that i bother much with Sata guns anymore but from what i gather the 4000 RP hasnt been recieved that well and most folk i talk to prefer the older 3000 RP model ,even my rep admited as much after being pushed but he has to sell what he has to sell ;-)
as for RP guns useing more paint than HVLP it actualy depends on the paint as the reverse can be true ,higher viscosity material ie clearcoat requires more velocity to get it to the panel ,RP guns provide the added momentum to enable this , with a HVLP heavier less atomised materials can drop out of flight and not actualy transfer to the panel ,with lighter materials HVLP wins as there is less bounce back and it will also achive better atomisation than it would with higher viscosity material so it is simply not all about the finish quality when it comes to RP guns ,for clear and HS materials they actulaly save more paint than HVLP when it comes to spraying the material they where designed to spray
heres an example of just how efective higher pressure is when it comes to transfer rates and finish quality ,the latest Devilbiss JGA Pro conventional HIGH PRESSURE guns which are concidered thier finest refinishing guns [sadly not legal in a bodyshop] actualy have transfer rates of 63% ,to be compliant requires only 65%
claimed transfer rates can be very deceptive and that is how HVLP is often mis sold or mis understood ,conventional spray equipment in the hands of an experianced sprayer is not actualy the vilian it has been made out to be and from a painters point of view i would rather sacrifice a little more paint to the booth than have to sand off even more material to correct orange peel
RP overall is a good compromise if you have to choose only one gun ,for basecoats then yes definatly HVLP all the way
BTW if you want guns that will imho outperform Sata at half the price look no further than Walcom guns my old FX HA was one of the finest clearcoating guns i have ever used ,i sold my sata RP within a week of buying the Walcom ;-),currently i am useing an Optima 900i by Bersch and Fratscher ,simply sureal and agian imho superior to any Sata model i have ver used