I switched from Sonar to Studio One when Gibson killed Sonar. I started by getting the fully functional 30 demo of Studio One Pro and figured out if I could quickly learn Studio One. There are excellent, official tutorials on YouTube. Also, Studio One is much easier to use and learn than Sonar. Almost everything is either immediately available in the unified interface, or at most, one click deep. I suggest you try this approach.
Also, v3.x is still very usable, but if you find that you like Studio One, I suggest you go with Studio One Pro v4.x. If you are patient, Studio One Pro is available 1/2 price a couple times if year. Also, you could write Studio One sales and see if you can still get a discounted Studio One Pro license as a competitive cross grade for Sonar. I bought Studio One Pro as a competitive cossgrade. It’s a good discount.
Finally, as a previous Sonar owner, I can’t say enough good things about Studio One. There’s no weird bugs that crash your project, there are no silly workarounds to get things to work, there’s no saving every 10 minutes because you are worried it will crash, etc. Studio One is supremely more stable and usable than Sonar and is well worth the investment in time to learn and money spent.