been using my vfl 4480.1 for a couple of weeks now, it puts out great power, blows my hifonics bxi 1610D out of the water and it never gets warm running full blast during a 2 hour drive at .5 ohms. One thing to note, my friend tried it on his car, and it didnt perform very well because his electricals were **** at 12.5-12.8 volts basically he had to bass boost +12db and gains to 70% to get any real volume off his 500 rms sub. With this amp you gotta maintain at the very minimum of 13 volts and up or else output drops a lot, i only needed gains at 50% and all bass boost off to get full output from my FIQ15 with my electricals at a steady 13.9-14.2 volts.
only frustrating thing its 4 gauge inputs so you either have to use a reducer or a short distro block run. Also it only has rca inputs but no outputs so its harder to run multiple of these if you normally daisy chain stuff.
my buddy was using 4 gauge only and that also limited the power it puts out.
All in all, its a very efficient amp but you gotta treat it right, like taking it out to dates, buying it chocolates, cooking it dinner etc..