http://forums.w5j6stm77zs6652pgsij4awcjeel3eco7kvipheu6mtr623eyyehj4yd.onion/t/ubiquity-lvm-tpm/585
I have only ever seen it used as the default installer for Ubuntu derivatives (whether those be official flavors like Ubuntu MATE or unofficial spinoffs like Mint, Trisquel, KXStudio, ChaletOS, etc). From having tried to work with its code, it is not fun to work with and those I know who have worked on it professionally were… less than thrilled. Even before it was finally deprecated it was being called outdated and bitrotten.