Pass xa30.5 vs First Watt F6

My good friend runs his Quad 57's (three stack 6 panels total) with the Quad tube amps (yeah 6 of them) designed for these speakers he had them recapped etc and they sound wonderful. Defiantly something to look at if you would consider tubes instead of the SS amp. I'm actually surprised at the bass he get along with the liquid mids and highs very detailed and of course that Quad sound.

I had a conversation with Mark at Reno Hifi regarding the F6 vs. the Pass, (I was interested in the F6). Basically, they both sound lovely, but the F6 would not have much reserve power when faced with a demanding speaker impedance at low frequencies.
Whereas, the XA30.5 has power to spare and performs well past it's rated wattage. 

He said speaker specs and sensitivity become more important when considering the F6.

I read recently that Nelson Pass is going to have Pass Labs make his First Watt stuff now…a good idea as I don't see any advantage to him building these things in his kitchen (metaphorically of course).

I would also be interested in a general comparison of these amps--same designer, very different approach (less is more vs. more is more). I'd love to see Nelson offer more First Watt monoblocks based on slightly higher powered designs like the F6 (i.e. more that the 10 wpc SIT 1s).