I don't doubt that a low mass faucet will have less foaming on the initial pour, but to what degree?
It would have to be a substantial difference for me to consider changing my faucets. All I've seen so far is marketing hype, with no test results to back up the hype.
Like I said, I don't doubt there is a difference, but how much? Is 10-20% difference in foaming on my first pour worth changing out my faucets? No way.
Is 50% difference worth it? Maybe, but I'm going to have to see some unbiased test results before I will believe a low mass faucet will make 50% difference in foam on the initial pour.
I have Intertap flow control faucets, in an 80F environment, serving 40F beer. For the first pour of the day I turn down the flow to minimum, and put only about 1-2oz in the glass. Of course it foams, there's no way it's not going to foam with a 40 degree temperature differential. While I am disposing of that first 1-2oz (down my throat), the faucet is being chilled because it's now full of 40F beer. I open the flow control all the way, and fill up the glass with no foaming problems.
Would a low mass faucet make a difference? Sure, but how much? Enough to justify the expense of new faucets? I don't see that happening, and I won't until I see some unbiased test results.