Hey Mia - the Pentair can operate below 2800 ppm, all the way down to 2600 ppm before stuff gets super-bad. The major downside of running it below 2800 is a drop-off in efficiency.
Also, the low-salt chlorinators do not handle large pools (yet.) So if your pool is 30K or bigger, you may have a couple years before they put one out for you.
I have not seen all that much interest in them, but that is probably because they are focusing on the Canada market first.