I've been down the alt tech rabbit hole, everything from Firewire to Stretch to XTR to FutureFlex and more. PU still feels the best. In my hand it might feel heavier than EPS, but in the water it carries so much more inertia and momentum than EPS. EPS might flick up to a fast speed at first, but it doesn't hold it. PU gets faster and faster, higher top end. Like throwing a baseball (PU) versus throwing a tennis ball (EPS).
I've had about 5 firewires in the past, my friend owns a small shop and lets me buy whatever at cost, and I can say that all the boards have been good. Never had a dud. BUTTTTT, I never had a magic one either. They sat somewhere between a decent board and just below a really good board.. Rode them for a few months then sold them. All my truly magic boards have come from working with a shaper. Most of the time not even meeting in person, but via email or text then mailing checks or sending paypal/venmo for deposit and paying balance when pick up. Takes about 1-3 iterations of a shape before we get supernatural results.
The one really good FW was a stock Tomo Nano. At 5'5 it's volume was so tiny for me at 6'1 190, but it went really well. Always thought about getting a thicker one via XTR. But you couldn't do that with FW.
FW is genius in their website, prod descriptions, copy writing, etc. They've captured people who want to nerd out on boards (all of us) and packaged it in a sleek design, logos, branding etc. I understand why people buy in and get them, but they are expensive and non customizable. Craftsmanship is around average in the board industry, imho.