Well - I "know" Sonar from the time I got a "light" version together with my E-MU 0404 PCI card. I Liked what I saw, and I bought and started using Home Studio 6 XL (and, of course, Project 5) shortly after that introduction. Within a few months I was using the full version of Sonar. Sonar was my "first love" DAW and I know my way in this program without much thinking.
However, one year ago I finally "jumped ship" to Cubase. I used Cubase and Sonar side-by-side for a long time, but decided that Cubase just fitted my workflow (especially MIDI) better than Sonar. By now I seldom use Sonar, but I still keep it around for older projects. If I would buy any upgrades for Sonar remains to be seen. It depends on the costs.
If Sonar gets resurrected (in what form remains to be seen), I will gladly keep it around for some time. However, Cubase 9.5 Pro is, and will stay, my prime DAW at this moment (especially now I got HALion 6 to build my own patches, and use note-expression for play back a lot).
Another point would be the Cakewalk instruments. I still use Dimension Pro, Z3TA+ 2 and Rapture. If those would get some payed-for updates (or expansions), I think I will buy these.