Good software for watching videos on Mac?
This answer will be short: VLC. Has everything you need except the rotation. It's a media player, not a video editor.

To alter the playback speed in VLC: Go to to Playback → Playback Speed. You can also alter the playback speed using ⌘= and ⌘-.

For rotation, as user Iwillnotexist Idonotexist notes in the comments below, you can go to Window → Video Effects → Geometry → Transform.

Bonus: A list of some VLC keyboard shortcuts for OS X.