Pixelmator or Affinity (beta) if you do no want to use Photoshop for your major edits.
View NX and Capture NX both have OS X versions. You can do the same corrections that you did on Windows.
You will need to spend some time in your favorite search engine.
For a photo manager, well that is a can of worms.
Lightroom
Photos (beta at the moment)
Corel Aftershot Pro 2
Capture One
DXO
Darktable
Seem to be the major players.
Lightroom is most popular, and the upcoming 6 will have some nice new features. Some people (and me) fear the eventual subscription requirement, and hate Adobe for pushing it.
Photos (in beta form), lacks certain features that advanced users want like advanced tagging. It seems to be more an iPhoto replacement than Aperture. If that works for you, it will be free. Will it update into a nice application like FCP X or forever be an iPhoto? The issue is hotly debated, but my crystal ball is no better than the other guy's magic eight-ball at prognostication.
Corel Aftershot is less widely supported with plugins than Lightroom. I have seen exactly ONE review that indicated RAW imports were of lower quality.
Capture One The most expensive of the lot. Many, but certainly not all, claim it has the best RAW import. It is the workflow most similar to Aperture. For editing photos, it is pretty powerful. Its DAM features are less highly regarded, but better that what is currently in the Photos beta.
DXO Well these guys made their name in lens corrections, so you better believe that is in the bag here. I heard it described as an engineering tool. It is powerful, but hard to use. From my admittedly limited experience with it, I am inclined to agree.
Darktable Free and open source. Very powerful, but a difficult UI for me. It has a dedicated following. Certainly watch a few youtube videos. It has a good selection of powerful tools at an unbeatable price.
Picasa Some folks like it. Not as powerful as the others on this list (save Photos perhaps). Google's terms of service and NSA level of going through your data may not be acceptable to you.
Also ran
Digikam Has a nice feature set, but installing on a Mac is not as easy as Linux.
iPhoto Already on your new Mac, but a lame duck as it is about to be replaced with Photos. Has a decent tagging system and facial recognition which can be handy in a large family. While it works with Yosemite, it will break at some future point and no further support is coming. That said, Apple RAW imports are in the OS, so it will work with newer cameras without an update.
Aperture For $80, it has the same major drawback as your free iPhotos. You get better editing, more powerful management and tagging, and plugin support from 3rd parties. Like iPhoto, it works in Yosemite, but no promises for future OS updates. As a new user, I would say that unless you REALLY, REALLY fall in love with Aperture (and a tragic romance that is destined to be), do not spend money here.