When I was shopping my new Envoy last year, I looked at the Aquafresh system (which is a self dosing Baqua system only) but passed on it for the following reasons: 1. Found it too expensive (about $1,200.00 extra, plus the costs of special chemical refills, if I remember) and 2. I am on well water which the dealer did not recommend with Baqua.
The Everfresh system is a bit of misnomer, I think. Basically, it means the tub uses Ozone (which is standard on all HS tubs now) and Dichlor/MPS for dosing and shocking and the N2 cartridge. As far as I know, the only other component of the Everfresh system is the pre-filter that you use when filling your tub. I had been using this pre-filter for the past 12 years anyway. There are the other usual chemicals that carry the Everfresh name, but this seems to be the HS brand. (ph up, ph down, etc)
Finally, I'm glad I passed on the Aquafresh system because the more I hear about Baqua, the less I like it. It seems it is easy to overdose, there is a scum ring problem and there are questions as to its effect on some plastics. I am in the "wait and see" camp (for about another 10 years) on Baqua. :-/
And personally, I like the Dichlor/MPS system anyway. Dosing after each use leaves no chemical smell when you are ready to use it again. This is much nicer than my old bromide floater system where I could have some chemical odor on occasion.
I say drop the Aquafresh and get the SpAudio instead!!