Marina,
I am a Nordic dealer. I have been selling Nordic for three years now and so far have been impressed with the quality. They are a simple spa so there really is not much that can go wrong. The components used are from quality manufacturers (Waterway, Balboa, AquaFlo) and if you get the tub with the Title 20 insulation they have been efficient here in Wisconsin. I have no real experience with Solana other than knowing they are a Watkins brand.
I personally like the Nordic Retreat but if you prefer the barrier free seating, then the Escape would be the better fit. And with the price points that Nordic generally sell for, I don't personally think there is a better quality unit for the price.