Another ex-Sonar user here, since version 5 up until X1. I think Sonar has some really cool features, like Bounce in Place (which is a big one I would like to have in Cubase) and the waveform preview on tracks/busses. But it doesn’t have enough to make me miss it. Things that I think you would enjoy in Cubase are:
1- This is a very simple feature, but oh so good. When you press and hold the middle mouse button, the cursor turns into a hand that enables you to drag across and easily navigate through the project. Like I said, very simply. But now I don’t have to use the directional keys as it was the case with Sonar.
2- If you use big Sample Libraries, like those from EWQL and VSL, then I advice to get into Expression Maps. They have incredible power when it comes to creating your own keyswitches and managing articulations in a cleaner fashion than the traditional multiout way (which is still a valid workflow, btw).
3- For multiple processes with a press of a button, nothing beats the Macro Editor. This is definitely not found in Sonar, and it is super powerful for speeding up your workflow. Must check out if you haven’t already.
4- Another nice feature in Cubase is Variaudio, which now lets you harmonize a melody on the spot with the help of the new Chord Track. Really nice when you wanna try out different harmonies or how something would sound harmonized. The quality and power of Variaudio is MUCH better than V-Vocal in Sonar. Since I mentioned the Chord Track, you can use it to try harmonic ideas for your songs without having to spend too much time recording, especially if you’re not good playing the keyboard.
5- The Audio Pool is something I use all the time to clean up my projects by getting rid of scratch takes that I will not use. Much simpler way of doing it than using the CWAF Tool, and you don’t have to leave the project.
6- Automation Lanes and modes. Nuff said.
There’s plenty more I could mention, but those are the ones I could think of for now (plus I have to get ready for a gig, )
Hope these help!