Whenever I've A-B'd the same model new guitar in red spruce and Sitka spruce, I've preferred the Sitka. Most of the time, I had no idea which was which initially, preferred one over the other, and then realized that they had different top woods. I have a red-spruce-topped guitar that I bought used, and it sounds great. Of course, I have no idea what it sounded like when new. People often claim that red spruce will open up and surpass Sitka with time. On the one hand, I do believe that guitars do open up. On the other hand, I'd never be able to bring myself to buy the guitar I liked less in the store, on the promise that it would magically transform with time. This isn't a dig at red spruce fans. Like I said, I have one guitar topped with red spruce (and a few mandolins) that I like very much. It may well be that it needs time to loosen up.
As far as finishes go, I've never heard a convincing argument that one is better than another with regard to tone. Most luthiers I've talked to -- many of whom have tried multiple finishes -- say that thickness is the most important factor. Violins usually use a much softer varnish finish than anything you'll find on a factory guitar, hand-applied using a pad in the French polishing method. Older mandolins also use oil-based varnishes. Different finishes definitely have different appearance and wear characteristics. Personally, I think the bragging rights that come with using nitrocellulose aren't worth the hassles. My F-512 does look mighty nice with its nitro skin, but so do other guitars I have with a variety of other finishes. Nitro is easier to repair but some of the modern finishes are inherently tougher and thus perhaps less likely to need repair. Obviously, I wouldn't avoid buying a guitar with nitro -- not in the least. But at the same time, I really don't consider it an advantage of any sort, either. Even if the finish has some influence on tone, it will be dwarfed by numerous other factors that exert a far larger effect -- like choice of picks and strings, not to mention construction methods and wood choices.
I actually feel pretty much the same about dovetail necks as I do about nitro finishes. Yes, they're traditional and, yes, they can function extremely well. But so can other arrangements, including bolt-on necks. I've encountered guitars with removable necks that mate with the body via three metal contact points that sound absolutely fantastic. Again, I've got guitars with dovetail necks and there isn't a thing wrong with them, except perhaps the cost associated with the more intensive labor to get them right and the potential for small errors to creep in. Not knocking dovetails by any means; just saying I don't consider them a big plus just because Martin used them back in the day and, for the most part, continues to do so.
Guild is justly proud of its illustrious history and it makes sense that it should emphasize continuity of design and construction for marketing purposes, if nothing else. So, I don't have a problem with the company's retention of dovetail neck joints and nitrocellulose finishes. But honestly, I don't consider either of those features to be a particular plus, either. I'm sure others will disagree and I don't think there's a right answer here, just a matter of personal opinion. Hope I haven't antagonized anyone. It certainly isn't my intent.
