After effects is better honestly, you can do more stuff in there and actually do it smoother. It takes a while to get the hang of it but it's pretty nice!!
After effects usually used for making or adding effect to a video, Sony Vegas used for basic video editing. Better comparing between Sony Vegas and Premiere Pro if you looking for basic video editor.
After effects and a lot of painkillers. Neither software is perfect. However I prefer AE mainly because of the integration with the rest of the Adobe Suite