Premiere Pro and Vegas are non-linear editors---i.e., they excel at chopping long clips of video into pieces and then assembling them in time.
After Effects is a compositing and motion graphics application---i.e., it excels at layering moving images on top of one another and animating things.
If you want to animate text and put that over video, then After Effects is the right tool for the job.
Your question about audio and green bars is confusing. I'm not sure what you're asking. See this page to see how After Effects deals with previews of video and audio; that should clear things up.
I very strongly recommend that you work your way through the getting started materials here to learn After Effects. The more effort you put into learning the basics up front, the less frustrating things will be. After Effects is not an intuituve application that you can just start using by pressing buttons.
What I meant by audio and green bars is that for example when take premiere pro for an example when you drag a clip to the timeline it labels the audio and video in the timeline, but after effects just has a green bar.
So would you suggest this program for a person who wants to regulary do some basic 5-20 minute videos in 1080P. Overall, just importing clips and rendering. Nothing too fancy.
The reason I'm trying to get out of sony vegas is that it just takes too long to render with a 6 core cpu, and it doesn't have that much high quality for a 1080p video.
After Effects doesn't have separate tracks for video and audio. After Effects is a program for manipulating images, not audio; the audio is just there for reference. An NLE like Premiere Pro deals with audio tracks in a much, much deeper way---as does Audition. That's why After Effects is integrated with Premiere Pro and Audition.
> So would you suggest this program for a person who wants to regulary do some basic 5-20 minute videos in 1080P. Overall, just importing clips and rendering. Nothing too fancy.
As I said, if you need a program to import video, overlay something onto it, and then export the video to a variety of formats, then After Effects is the right tool for the job.
Since there's currently a 50% off deal going for the entire suite, it's actually cheaper to get the entire Creative Suite than to just get After Effects by itself.