I did several hours with the T-400 tonight, including an A/B test with my Gretsch Country Club. Sound wise, the two guitars are similar with the T-400 being a bit brighter. The Country Club is a bit huskier sounding, but you'd be hard pressed to tell the difference unless you were purposely trying to pick out the details. So, here are the details:
The Anti-Hums and the Filtertrons are the same size which suggests similar bobbin spacing. Both have a focused sound that doesn't turn to sonic mush. I don't have an inductance meter, but I suspect that the Filtertrons are roughly similar in output to the Anti-Hums as well. The Guild pickups might be a bit stronger, but they are definitely in the same neighborhood output-wise. The pickup spacing is quite different, however, being 3/4" more broad on the Guild. The neck pickup is 3/8" farther from the bridge and the bridge pickup is 3/8" closer to the bridge on the Guild so that when only one pickup is selected the sound is more enhanced in the direction of that pickup. On the other hand, when both pickups are selected on the Guild they are covering a wider area of the string with more variation in harmonic output so the sound on both pickups tends to be pretty mellow on the Guild. Mellow, not indistinct, however.
The specs on these guitars don't differ all that much, both are 17" guitars with solid spruce tops and maple bodies. The Gretsch has a slightly longer scale at 25.5" as opposed to 24.75" on the Guild. That's 3% difference in string tension (I use the same string gauges on both guitars) so the effect is minimal, probably below the threshold of perception. The Guild is 2" deep, the Gretsch 2.75" deep but it has a soundpost so it is less resonant. I would rate them as functionally equal, albeit slightly different.
The Guild pickups seem to interact differently with the front end of the amp, whether I'm talking about a Deluxe Reverb or one of my beloved Winfield's. When you push it a bit the Guild pickups have a complex, interesting sound. I don't know how to describe it, but it's delightful. I'm not much for distortion, but when I play Rock, etc, I like to ride the edge, neither clean nor broken up. The Guild pickup is a good tool for this. Likewise, the EF86 front end in my Winfield amps does much the same thing, having a broad range that is not entirely linear but not truly broken up. Pairing these pickups with one of these amps is sublime. It is an interesting sound and works for a lot of different things.
In the flick of the pickup switch the T-400 can go from Don Rich Chik'n Pik'n to Wes Montgomery Jazz sounds. That is impressive! You can cruise endlessly on both pickups and cover a wide range of country and Rock sounds just by virtue of your technique. The widely spaced pickups respond well to pick positioning so you can get mellow just by picking further towards the neck. If you want to use pinch harmonics the bridge pickup will detect those overtones and send them along to the amp yielding a sound that is strained, yet mellow all at the same time.
The tone pots add versatility but are hardly a necessity. I did experiment with backing the neck tone control down and could do a pretty decent take on the late Jim Hall's sound through the neck pickup. With the tone controls all the way up and both pickups selected Chet Atkins' sound was there for the taking. For this task, the T-400 is every bit as capable as a Gretsch . . . which is a good way to draw to a conclusion.
I have 13-14 guitars and none of these guitars have ever given me anything but great sound and great reliability. I've tweaked here and there, pickup swaps, etc, but at the end of the day I can probably play a gig on any of my archtops and do just fine. Sometimes the choice of which instrument to take to a gig is esoteric. Having an old collar bone injury on my left shoulder, weight has become a major concern, even a six pound guitar can become uncomfortable by the end of a gig. The Guild wins big in this dimension, weighing about a pound less than my Country Gent. I think that this T-400 will be played and quite frequently.
