Don't think for a moment that Photos is remotely a replacement for Aperture. The two main candidates to replace Aperture are Lightroom and Capture One Pro.
After buying Aperture full price just before it was discontinued, I switched to Lightroom. It lacks some features I want from iPhoto, and so I still use both on an older OS version. With iPhoto 8 you can export all the information, including comments and geotags, using the Phoshare (free 3rd party) application and get the benefits of both tools (with some substantial extra hassle).