I for one am no longer a fan of Sony Vegas. I have Sony Vegas and Sound Forge. I used them on videos all the time. I use to export an avi format and then import that video into Sonar. Then I worked on the audio track. Once the audio is complete I export the audio from Sonar and import that back into Sony Vegas. From there I export the video into what ever format I choose.
The problem is the avi format is huge. I just shot a new video series that would be 92 gigs of footage in avi. but it is under a gig in mp4 format. I am glad that Sonar has expanded the format options in one of their updates to X3. This makes things a lot easier.
The problem I have is sometimes I get a green tint to the video in Vegas. This is in the mp4 and mov formats. The problem seems to be a conflict issue with Sony Vegas and Quicktime. I was able to isolate the issue only to discover that the problem is only in Sony Vegas.
I say all of this because if your looking for a third part solution to video while working with Sonar you might want to consider your options. Before you spend your hard earned money on a third party video program you should look to see what else is out there.
Just Yesterday I purchased Adobe Premier. I ran a test and found out that all the video that will not work right inside Sony Vegas works flawlessly in premier. Adobe just changed it's business model to a subscription based software model.
Instead of shelling out expensive hard earned money for Vegas you can get the full version of everything adobe makes including adobe premier for just 50 bucks. When you activate your account you also get connected with your own ULR. You also get things like Photoshop and Adobe Elements which gives you the ability to animate graphics in your video.
I can already tell from just the little work I have done with Adobe Premier that it is an awesome program. I personally like it better than Sony Vegas and 50 bucks is a lot cheaper then the 499.00 for the full Vegas suite.
For my situation adobe Premier and elements are now my favorite applications for video. Sonar X3 remains my favorite application for audio. I will probably use a combination of these too products when I produce videos in the future.