It is very DARK in person, which really to me hearkens back to the 1950s. I like it. The whole thing looks, feels and sounds vintage. It almost sounds as "vintage" as my Hummingbird Vintage, in fact, and it holds its own very well against it which really says something. My Hummingbird Vintage retails for like 4x the amount as the D-20. Even a regular Hummingbird retails for 3x the price.
But, being a square-shouldered, mahogany dreadnought, my Gibson Hummingbird Vintage is the closest direct comparison for the D-20, despite the major differences of top wood (mahogany vs. torrefied sitka spruce), scale length (Gibson is 24.75" and D-20 is apparently 25-5/8"? which is oddly even longer than Martin's 25.5"), and of course the huge difference of innards/manufacture.
It really breathes. It is loud, at least for a mahogany guitar, and maybe loud in general. It is certainly louder than a Martin D-15M, as loud as my Hummingbird (Hummingbird has the shorter scale though), and perhaps as loud as most any dreadnought within reason. It definitely has the sweetness of a mahogany top, and you would not mistake it for sitka spruce, but I did not want another sitka spruce. I also did not necessarily want a loud guitar, but I didn't want a heavily compressed or muted one either. Happily, this is just right. It's extremely dynamic, which is what you want in a guitar. Some guitars (looking at you, Martin) seem to have one volume setting: 11, which is great when you want it but can be a problem if it happens accidentally. Other guitars compress and bottom out and don't quite get the dynamic loudness when you might really want it (I like to really bang with a pick for a crescendo sometimes, and no, you don't want the guitar to drown our your voice, but you do want it to be able to get loud enough to support your voice if you're really having a wail). Again, this D-20 doesn't disappoint.
The case is the coolest I've ever had a guitar ship with. Love the green lining and the built-in humidifier. I will eventually buy a Hiscox for this guitar anyway, but still. It came with fun case candy too (look! review the guitar and get goodies! maybe I'll just copy/paste this--if so, better remember to delete this part)
The setup feels good to me. I will not change it. Even with brand new strings, the guitar does not sound harsh (one of my main complaints with strings and with Martins--too much pizzazz! give me dead strings instead!). I look forward to trying different types of strings, but it seems like it will probably sound good with anything from Pure Nickel to even the really garish and harsh-sounding coated strings.
The fit and finish is not perfect. I don't care, personally. You can't tell unless you stick your head in the soundhole, and it affects nothing. The fit/finish on the outside is pretty darn close to perfect if not perfect. Neck set does seem perfect. Fit/finish/setup is at least on-par with Martin/Gibson, maybe better.
I find that for fingerpicking, I'm plucking the strings maybe a little harder than I should. This might mean it's a little quieter for fingerpicking, or it might just mean the setup is good enough that I'm too heavy-handed. (I am definitely a heavy-handed fingerpicker) I don't think the trebles are too quiet for fingerstyle or anything like that, but then, I am one of those weirdoes who happily fingerpicks a dreadnought or jumbo.
In general, it's just got a really sweet, vintage-sounding tone with strong string separation, a thrummy and deep bass (rather than a popping one). I think it's probably louder and less dark than one would expect from an all-mahogany guitar. It does have quite a CRACK on the upper-midrange. This could be the new strings. It is not undesirable and I think contrasts with some mahogany guitars. When you really get it going, it has a nice jangle (in a good way) that is kind of a weird hybrid of Gibson and Martin, and again, so vintage-sounding.
Playing it, I'm not specifically reminded of anything. I'm not really reminded of Guilds of my past, nor of other all-mahogany dreadnoughts. If I had picked it up in the shop, I would have said it was one of the best guitars in there. If it was a brand I did not recognize, I would have taken notice of that brand; or a brand I didn't care for (such as Taylor), I would have re-evaluated that brand. If it were an import (Guild or otherwise), I'd have to begin thinking twice about avoiding imports. But, it is a Guild, the name of an old friend, and made right here in the US of A by the team of another old friend.
I really like the neck. It seems maybe a little chunkier and (again) more vintage. Oh yeah, and as the 1-11/16" nut width was what worried me so much (and only love of Guild got me to take the plunge), it seems like I'm totally fine with it. Yes, it is a little narrow for me, and I screw up a bit more, but I'm managing, and eventually I may actually screw up less in other areas (it does maybe thumb-fretting easier). I think the chunkiness of the neck helps me a little, too. Switching from the D-20 to my Gibsons (a whole 1/32" difference!) seems fine. I'll see how I do switching between the D-20 and my Martins (1/16" difference at the nut which I think makes a sizable difference at the bridge).
In the end, what sticks in my mind is that vintage, chimy tone. It looks like a new guitar, but it sounds like an old one. It came to me in tune. The tuners, by the way, are excellent. They seem perhaps higher than usual ratio, which I really like, are buttery smooth, and the plastic buttons feel kind of nice. I think they are Grovers (which are imports, by the way, made in China these days), but Grover seems to continually up their game. I'd still prefer USA-made tuners on a USA-made guitar, but what can you do. That is about the only corner cut other than the lack of blind/binding, and even my Gibson SJ-200 with special edition art deco tuners had Chinese-made Grovers.
One thing I still wonder about is the "satin varnish." I wonder how it differs from satin nitrocellulose lacquer.
I think that about sums up my wide variety of thoughts, but if anyone had questions or was trying to decide whether to purchase, I'm happy to think more.