Unity3d
Features
Unity is a very popular full-featured game engine and development environment designed to let you focus on creating games and worry less about the technology used to create it. The game engine itself is a 3d, OpenGL-based renderer, with advanced lighting, physics, terrain, audio, and even built-in networking. Code for the game you create can be written in C# or Javascript - whichever you're more comfortable with.
Deployment
With Unity, you can create games for Mac, iPhone, iPad, Android, Windows, PS3, Xbox 360, Nintendo Wii, and even web browsers. You truly can reach every major platform to get the widest possible audience for your game.
Cost
The best part about Unity? You can use it absolutely free. Unity comes in two editions, the base version which is free, and Unity Pro for $1500. There are also separate add-ons for some specific platforms such as iOS and Android deployment. Compare the different Unity licenses.
Recommended Resources
Unity is a great choice for Mac and iOS game development, there's little reason to not learn to use it. If you're interested, grab a book and read some tutorials. You can even hire Unity developers to get your project started if you're looking for a serious start.
Book: Unity 3.x Game Development Essentials
Tutorials: Official Unity Tutorials, Unity Training Videos
Developers: Graveck Interactive — Long-time professional Unity developers with an extensive high-profile portfolio.
