First Watt F7 owners, impressions?

I have two W4S SX-1000 mono block amps [not the R version].  I'm looking for a preamp and considering the W4S STP-SE [not sure if I want the 2 upgrades, though.].

Having said the former, I am also considering an [Swiss Army Knife all in one unit]; i.e., the Musical Fidelity M6 Encore 225 [Amp (225W per channel), PreAmp, DAC, CD plus Music server.

My Speakers: Jas "Odin" 2.5-way Tower Speakers [89dB; 4ohm; 29-60000Hz; 220W (normal handling power); 1000W (transient power 10ms).

Does anyone have any thoughts between the W4S components and the Musical Fidelity [all in one unit]?

I wanted to update this thread because I just got the Wyred 4 Sound STP-SE preamp (with stage 2 upgrades) and it brings out the best in the F7 to my ears, compared to the others I listed above. I am sure many others have this amp by now, given all the positive reviews, and I would love to hear what you have tried and your experiences!

@roncagg 
Thanks, Ron. Good info.

Lowrider, the F7 controls the bass very well, no doubt due to the excellent damping factor. Mark is apt to focus on the sensitivity level rather then the impedance curve, and the gallos are easy to drive. See Srajan's response to my question about the pairing (in his feedback section). He found the F7 capable of driving several speakers well that "on paper" it shouldn't have been able to.

Fritzspeaks, the Carbon 7SE is on my list to try! Partly due to that review. What amplification are you using with those? 

For more info regarding the difference between the J2 & F7 (and the Pass SIT-1 mono blocks), check out John Richardson's Part Time Audiophile write up on all three amps with 3 different loudspeakers including Zu's Druid Mk. V, ATC's SCM 19 version 2 and my own Fritz Carbon 7SE's.
https://parttimeaudiophile.com/2016/09/09/review-j2-sit-1-and-f7-first-watt-amplifiers-by-nelson-pas...

Also, check out the Stereophile review by Herb Reichert of the J2 with half a dozen loudspeakers at http://www.stereophile.com/content/first-watt-j2-power-amplifier#mEgFspqof6P0VdkH.99

I called Reno HiFi regarding the F6, F7 and was told that they probably couldn't drive my Gallo Classico floorstanders (88dB, 4 ohm). How well does the F7 push the bass of your Gallo 3.1's?

I have not, I rely on 6moons for those comparisons. I have had the F4 and Aleph 30, and prefer this to both. The Shrimp preamp I use is a good match, very low output impedance. There are others too but I agree it takes some looking. Worth the effort though! 

I'm interested in hearing about the F7. The input impedance spec of 10kHz makes it hard to find a suitable match with a tube preamp.

Have you compared the F7 with the F6?