Old post but I'd love to chime in. I'll keep it simple.

Iwata LPH400 is a HVLP = slow
supernova is "compliant" = fast

Sata HVLP = slow
SATA RP is compliant = fast "my gun of choice"

The difference ?

HVLP gets high transfer rates due to lower attomization and therefor bigger droplets that hit the substrate and stay there. Good for basecoat.

Supernova, SATA RP, are "compliant" with laws but are not restricted to the material output a HVLP is subjected to. Therefor you get a faster gun but you also lose a little transfer rate because it atomizes more than a HVLP. For clear go with a compliant gun and lay down a very nice clear coat. You can dial your air down a bit and increase the Tranfer rate of the RP and have best of both in the same gun.

In the end for most DIY or beginners buy what you like. If you like a cheap one and it makes you happy then you will do good work.

My arsenal of choice. happy painting !!!!