Thanks all for your comments and observations! So far I'm very impressed with the Manhattan Special. Its not a vintage guitar, and in some ways I'd say its like an 'idealized' version of an X-175. But it feels great to play, the 'box' while not loud is quite acoustically resonant, and the overall impression is very high-quality.
I've owned a few X-500s and X-700s (but never an X-175) of the more modern 'wider' body style, but have always admired the more 'svelte' early style, which IMO really shows the Epiphone heritage of early Guild archtops. Like those earlier models, this one is light and resonant, with a full but comfortable neck. And of course it has the distinctive DeArmond 'replica' pickups, the original DeArmonds being one of my all-time favourite electric guitar sounds.
The new Guild 'replica' DeArmonds are perhaps the one thing about the Manhattan Special I'm a bit disappointed about. They do sound suggestive of the originals, with a lot of the unique frequency contour, and could be used in all the ways you'd expect (rockabilly, jump blues, etc.). Only if you can directly compare to the originals is it clear that the 'replicas' lack something of their sparkle and presence. The one thing I plan to do is install a pair of T-Armonds (luckily a local distributor here has a few pair).