As I started this thread I suppose I should chime in here.
Since 3-9-03 I bought a new Advanced Jumbo - I broke every rule in the book and ordered it through ebay over the net(Although the silking of the top in the photo did catch my eye) USA to Ireland - no way back there!
Luck was on my side and I'm very happy with it. Save for a dodgy adhesive on the pickguard I'd say the finish was grand(ended up buying a new guard from Gibson).There does seem to be a fairly broad consensus that there has been an improvement in quality control at Gibson over the past number of years.Playability was fine too.
The AJ doesn't have the sophistication of a Lowden, but it sure has it's place in my collection. As I can be heavy-handed on the strumming I welcome the "headroom" the AJ affords, and it's fret-spacing allows for easier tune-picking (e.g. playing a reel). As for sound, it's earthy and good to my ear.
As for rosewood or mahogany, I can only speak regarding Lowden O series. To my ear the rosewood gives greater bass, and all-round warmth. I prefer rosewood to mahogany. I presume there should be some comparison to identical Gibson models.
Good luck in your search.