We have a 303RLS on order. The factory is quite approachable and has been very forth coming when it comes to answering questions. Owners on the GD forum indicate that doesn't end once you have taken delivery so that is reassuring. Factory reps are frequent posters on the forum.
One issue I do have is their reluctance to make any changes at the factory. Our model has two options, free standing dinette and thermopane windows. Dealers here order them as matter of course. If you want fantastic fans etc, you have to go through the trouble of removing the old vents, installing the new, re sealing the roof and having parts left over. I guess they figure these are production efficiencies they need to maintain a price point but can be quite inconvenient for a new owner.
I will also be removing the 16's from my present rig and putting them on the GD. I'm just not comfortable with running smaller wheels on a unit that is 2K heavier, even if the 15's are rated to carry the weight.