I bought a Cal Spa last November. When I was looking, I saw a great deal on a Gulf Coast spa from a "warehouse" dealer. Checking it out, I found a great many people had problems with Gulf Coast honoring their warrantees. (If you don't mail in the card within ten days, the warrantee is void.) I can't vouch for it personally but that's what I was told.
Also, when the warehouse manager told me they could install the 220V wiring in my house for $200-300 (sight unseen), I became a bit more suspicious. I went with the Cal Spa which was a bit more expensive because there was a large reputable dealer in town who would service it and support the warrantee. I have had no trouble whatsoever so far.
Good luck in your selection!!!