I could not function without Wavelab. Been using it since version 4.
You can set Sonar to open an audio track in a Wave editor using the tools menu. Scook made a utility to set this up.
Just like a DAW, Wave editors all have different workflows. What seems unique to WaveLab is the way you can open tools and they remain open through out the session. All the others, including Sonar, you perform a task and the tool GUI closes forcing you to re open it every time you use it.
Take something simple like Gain.
I have played around with all the mainstream Wave editors and just like I always return to Sonar, I always return to Wave Lab. Possibly because I know it so well and all it's little shortcuts so I can work fast.
My other favorite I bought ( $50 lifetime) is Gold Wave
http://www.goldwave.ca/release.php I use it mostly for Batch conversion of MP3.
But I will play around with this Acoustica 7 and see what it's like.
I only use Wave Lab Elements ( $100 ) because the full version ( $400 ) is way more than I need.
And once you find something you like you keep your eyes out for a deal.