I have always read of great customer service from other members who have Grand Design units.
Unless it is recent, the GD fivers do not have the quiet air like that of the Lifestyle fivers.
The LS should have in in house built box frame over the GD.
We have a 2014 LS and it has been problem free, is solid, and has excellent fit and finish - especially on the interior.
I think you will be happy with either. Like a previous poster mentioned, dealers will be eager to move their LS inventory until LS/Evergreen decides what they are going to do. As of now, their doors are closed but they may reopen....time will tell. With that in mind, if you choose a LS, be sure you do a thorough PDI with your dealer and make him give a top rated after market warranty on the rig. All of the individual components will be covered by their own warranties including axles, a/c, appliances, etc.
2014 Lifestyle LS36FW
2013 Chevy 3500 DRW 4x4 Duramax/Allison