We have an Ann Sack's Onzen Tub - now called something else. We do love it, but haven't used very often (in house 6 years now). Scroll down about half way for picture - ours has jets, but we did not get inline heater. Haven't needed, as we insulated well before setting and the water stays warm.

Here is a link that might be useful: Onzen Tub

Thank you very much!

We have the Sorrento and love it. It holds heat beautifully and the material feels really nice. It's super solid. I will say it takes a ton of water to fill it, so make sure you have an on-demand heater or something like that.