Out of the 3, if you want a proven quality tub, buy the Artesian.
The Catalina of old, which was a decent tub is not the Catalina of now. It is a low end tub, made by Leisure Products, Inc. LPI makes the Dr Wellness brand. Both have poor insulation and weak shells. LPI is also not known for their customer service. There is a reason that it's $8495 base and has extra cost extras. I actually considered a LPI tub when I first started comparing tubs. The final straw was when I went to the local dealer. High pressure to buy, high pressure to finance, nothing included with the deal, not willing to let me look under the hood and really unwilling to answer anything more than basic questions.
The only hot tub called a mykonos that I found is a Euro tub that has either Gecko controls or Balboa controls. Gecko is better than the no name stuff but I would consider Gecko not as good as Balboa. If it's truly a private label, it's more than likely a Chinese tub and not worth what they are asking.