I have both on my keezer. I prefer the Perlick FC mechanism - up=faster flow, down=slower flow. The Intertap flows fastest at the center position, and moving either up or down from center slows the flow.
The tubing that goes on the Intertap growler filler is fairly large, and since I bottle from kegs with the growler filler (mostly for comps), the tubing doesn't always fit into the bottle. The Perlick 600 series growler filler fits perfectly into the Intertap standard nozzle.
If you think you might want nitro pours, get the Intertap. A $15 swappable stout nozzle is a lot cheaper, more convenient, and easier to clean than a dedicated stout faucet.
I don't have experience with the ball lock nozzle, but if you have a Beer Gun, that could probably be pretty useful. Again, I bottle from the growler filler, and it works just fine for me.
So, basically, you can't go wrong with either.
Base functionality I give to the Perlick for its mechanism.
Extended functionality I give to the Intertap mostly for the stout nozzle.
I think the Intertap is cheaper, or it used to be anyway, so if money's an issue, Intertap wins there, too.
Perlick wins for "fit & finish" only because I've read reports on here that some Intertaps have had some rough edges. It's a minor thing, probably not worth noting. Both my Intertaps and Perlicks are very well finished, and pour smoothly.
Replacement parts are available for both, usually as a kit.
