I have serviced many tubs of this type. They have an undeniable appeal, and the sample photos on that web site are certainly some nice-looking installations.
The one thing you need to know right off the bat is that this an open spa - like most in-grounds. Because of the the odd shape and the waterfalls, you really can't get a good insulating cover on the things, therefore you can't hope to keep them hot all the time. If you don't mind paying the cost of energy, you can run a timeclock on multiple cycles each day and have the heat set to keep it just warm, so you only have to kick the heater up the last five degrees or so. That costs less and the wait would be minimal if a huge heater is installed.
That might not be an issue if you are a casual user and want the thing mainly for the looks. If you are trying to get serious hydromassage on a regular basis, put in a fountain and go get a real hot tub from a major player.
