Personally, I always found vintage guitars
easier to maintain than the new stuff: IME they were built to a far higher standard than most of what's available today, in addition to which the seasoned air-dried woods used in their construction were more stable from the get-go (and even more so after seven decades of aging) and less likely to develop humidity-related gremlins as a result - not to mention that "tone you could eat with a spoon" you'll only get from a well-used/well-played Big Band-era veteran...
As far as the current stuff you mention, the now-discontinued Godin 5th Avenue acoustic is a latter-day iteration of the old student-level Kay and Harmony archtops of the 1950's, albeit with better materials/QC/playability; tone is what you'd expect - surprisingly good for what it is, quite versatile (I often fingerpick mine - sounds much like a 000 but with the characteristic archtop immediacy and midrange-forward projection), capable of a fair bit of volume (you'll need 13's or heavier - I'm using Martin Monels on mine for some authentic '40s vibe), but ultimately no real competition for a true caved-top instrument. If you must have a Gretsch, I'd avoid both the Synchro 100 and New Yorker 9555 (or its all-acoustic predecessor 9550) - neither of which is made to the structural/tonal standards of the Korean Electromatics (much less the MIJ Professional Series) and, in spite of the solid top on the latter, thin and strident-sounding to my ears - in favor of the discontinued 17" non-cut Synchro 400 (think George Michael); be advised that these are an underground favorite and, when/if available, can vary widely in price - that said, I've played a few and they're well worth the search...
If you're looking for a brand-new, all-solid/all-carved instrument at a reasonable price Loar and Eastman are the only real options, and each has its adherents - Loar has the vintage visual/tonal vibe (including an authentic '20s style thick deep-V neck, which I personally find daunting), whereas Eastman is a modern instrument in the post-Benedetto mold (broader frequency spectrum, more "polite" and less in-your-face, with modern neck contours and playability). IME Eastman's QC is also generally higher (Loars can have iffy neck geomatry -
extremely important in an archtop), and if you gotta have a 17-incher they're the only game in town under $4K; since you're looking for the Grady Martin "Gunfighter" tone in a new instrument (I'm still partial to the vintage stuff) I'd focus on a maple 16-incher, either the Loar LH-600/700 or Eastman AR805 - check out both and see which one suits you best...
