I just downloaded it a couple of days ago.
So far, it's not a lot different than Family Tree Maker 2 for Mac-- the plan page is laid out differently, and the photo boxes for the people in the trees are now colored-- pink for females and blue for males.
There is an improvement that makes a huge difference, and it was one that I would be hoping that FTM 3 for Mac would have: you can now link multiple media items at a time! Previously, you could import more than one media item at a time, but you could only link one at a time to a particular event. This made the process of importing and attaching media items to specific events in your ancestors' lives rather slow and frustrating.
Better yet, you no longer even need to use the "link" feature, unless you're linking to the photo assigned to the particular person in your tree. You can simply copy and paste! This saves a lot of time scrolling through the media items to to find the correct item. Now you can simply click on the item or items, click "copy" under the edit menu, click on the event you want to link the item to, click into the "media" box at the right, and then click on "paste" under the edit menu. A whole lot faster and easier, and a lot less chance of making the error of attaching the wrong item.
You can also delete multiple media items at a time, whereas you used to only be able to delete one at a time.
This in of itself has made FTM 3 worth the $30 to upgrade.