Welcome to our forum.
I did test the vista and was satisfied. But then I realized that the Vista has a larger pump. Not sure if that matters considering the tub is also larger. So if I was happy with the Vista performance, then you think I will be ok with the Envoy.. By the way I added Spaudio II as well. Not that you should decide based on that, but it was an added bonus.
The jets in the Caldera seem more active, and I love being able to flip the nozzle over to get a spin jet. I also like being able to shut down other jets to get more power where I want it.
As for your question, the Tahitian has two 2.5hp pumps, it is actually more powerful that Vista or Geneva, since it uses the same pumps but moves less water (360 gallons vs. 475)
WHAT ?!? Where on earth is this information coming from? You cant possibly believe that the same pump will move less water in one spa vs. another, by 115 gallons per minute no less?!? If this were the case, the only reason it would be happening is because the caldera jets are so small they restrict the flow, causing an uncomfortabe intensity in the jets and undue stress on the pump shortening it's life. Seriously, where is this information coming from?