The Vegas program is Connect HD, cheaper than the Aspect program required for Premiere Pro. (Premiere Pro is a 10 bit program and Vegas an 8 bit. That probably accounts for the difference and Aspect includes other “extras” such as transitions and Vegas includes many of those.) Connect HD is not required but it is a good program, will scene detect and create the cineform avi file automatically on capture and will also deinterlace. I personally use it and think it was the best $199 I spent but not everyone who does HDV uses it. You should probably use the trial version to see what you think.
JerryW