I did the survey and was sent a set of Firewire Boost. My go-to string is Tourna BH Silver 7 Tour. The Firewire Boost feels very similar to Hyper-G that I recently tested. Bite on the ball is similar, power levels are similar, launch angles are similar. Firewire Boost is a bit more comfortable hitting on both the sweetspot and when missing the sweetspot. However, it's also less crisp and feels like there's a lot more internal dampening of the impact. That more muted response feels like it is coming from the cross string.
I've got about four or five hours of hitting with it so far. Tension maintenance is better than average, and sensitivity to tension changes seems minor. There's some notching and wearing of the mains but it looks like it will last 10-12 hours before notching through.
Compared to my go-to string, Tourna Silver 7 Tour, Firewire Boost is lower powered, less crisp, and just slightly less comfortable. Tension maintenance feels about the same, and the Tourna may last a couple to a few hours longer from a pure durability standpoint. The S7T has consistent playability until just before it breaks and I haven't gotten to that point yet with the Firewire Boost.
So overall a good string that is a great alternative to Hyper-G for anyone that likes Hyper-G but wants a bit more comfort. The Firewire Boost cross string seems to be the primary culprit in it feeling so muted, so a crisper substitute may make the stringbed feel more lively. I think that anyone who switches from Hyper-G to Firewire Boost will have no issues with the transition.