I had the Vegas audio only version way-back-when which was initially offered to registered Sound Forge users at no cost. I forget if the offer came via email or the Sonic Foundry SF users group. When the opportunity (or need) to edit video arose, naturally I turned to Vegas due to my familiarity with Vegas audio.
When Vegas 1st appeared as an audio editor I was doing mostly midi and sampling, which it was (and still is) pretty lame at. But it was free to Sound Forge users so I grabbed it anyway. What really got my attention was when v2 added video support. Inspired me to start dabbling in video. It's audio and video editing capabilities have kept growing and I've been buying it ever since. Curious to me that it's not widely acknowledged as a premium audio editor. I recently did a multi camera video recording of a 5 hour benefit show after which my good friend who did the live mixing was good enough to hand me the 23 pre-fader audio tracks he had captured with Reaper. My original plan was to mix it down with Reaper but found it way easier to just pull it all into Vegas... mixing blind just can't compete with seeing who's doing what where on a stage with mics scattered all over the place. I always favored Sonar for its editing and routing capabilities but found Vegas can do it all... even mid-side/surround mixer-implemented encoding and decoding.