I can't speak firsthand about how well you can edit GoPro footage in Vegas Movie Studio. Based on posts in the Vegas Pro forum, it used to work well, then it worked very poorly for a long time, and then -- in a release just a week or so ago -- seems to work well again. Movie Studio has not had an update in quite some time, so its hard to say. As musicvid says, try a forum search... or perhaps someone with recent experience will post here.

But... GoPro cameras are tiny little cameras, and in many circumstances are not a suitable replacement for a regular camcorder -- depending on your needs, of course. There is no LCD (video) screen on the camera itself -- though I think you might be able to view the footage it is recording on your smart phone, by downloading an app and using a wifi connection to the GoPro. There is no zoom in/out like you have with a camcorder, though I think you can choose from several image width options in a configuration menu (i.e. super wide, regular wide, etc.)

GoPro cameras are awesome as body-wearable or vehicle mounted cameras. I've watched many AMAZING videos from GoPro cameras on the web, or in their in-store displays. It is an amazing product. But if you don't want another camcorder you might be better off with a digital camera of some kind, as most of them take pretty good video at this point, but still offer the convenience of zoom lenses, LCD displays, replaceable battery packs, etc.

If compatibility is a concern for you and you really want a small POV style action cam I can highly recommend the Sony HDR-AS100 and AS200 cameras. I use them on my motorcycle and have collected tons of mostly boring but visually beautiful files. I have had no real problems with Movie Studio 13 (platinum) other than my skills limitations. Recording in the Sony archive format (AVC-S) yields a beautiful video.

I just got a Hero4 Silver and have not edited its footage yet.
But I've been successfully editing 1080p footage from my Hero3+Black (which was apparently pickpocketed a few weeks ago) with VMS Platinum 11 for a couple years now.
I did notice (confirmed by very helpful GoPro tech) that for default 1040p W the Hero4 shows 2hr11m for a 32GB SD card vs. Hero3's 3hr20m. So the Hero4 has a higher default data rate that I cannot change. I don't know if that will be a problem with VMS, but I doubt it.