Hi there.
I'm curious if you have had a chance to wet test the Caldera Niagara? My experience wet testing both of those spas led me to give them very close overall ratings. for me the Niagara rated a bit higher on my list. Please don't take my word for it though. I would simply recommend you give the Niagara a try
I don't want to dissuade you since the Grandee is definitely a very good spa, but I was offered a price of $8900 for the Niagara with the cover lifter, steps, GFCI panel, delivery, setup, and chemical kit.
Assuming you could get a comparable price, I thought the significant cost difference between the two models should definitely make it worth your while to try the Niagara.
FYI: I'm not a dealer and am still trying to make my decision on which spa to purchase.
P.S. Some might point out that Caldera prices are going up due to increased fuel costs. However, the higher cost of fuel is affecting every manufacturer.