I recently spoke with Don Stewart to get his opinions on this as well. In summary his recommendation was to stick with the Firehawk, even though it would cost him a sale.
He was saying that despite the great advancement in black levels in pjs recently, that if I put up an ANSI checkerboard pattern and held up a piece of StudioTek material half way in one of the dark squares, that I would be surprised to see how much lighter the black level was on the ST material compared to the FH.
His main point was that people do not have a very good reference for bright white in their mind and have a hard time judging bright white without a simultaneous direct comparison to something even brighter. And that on the contrary, people do know what dark black looks like without any such reference.
He was saying that for his tastes at least, for home viewing he would rather have blacker looking blacks because the better black level is more satisfying since it is easily identifiable as such, whereas the whites will still look bright white even if they are a bit dimmer than they would appear on the StudioTek (and you wouldn't realize a difference, whereas with brighter blacks you would).
He also felt like the StudioTek would no doubt lower my ANSI CR and intra-scene CR compared to the Firehawk despite my room treatments unless it was close to a total bat cave (which I do not have).
Considering how much effort I've put into making adjustments to the room (velvet, rugs etc) to bring up my ANSI and intra-scene CR, and his point about having a bit better blacks with the Firehawk I've decided for now at least to stick with the Firehawk. Fortunately this is the cheaper option!