Once you've experienced the game-changing productivity of a compound mitre saw, it's hard to imagine living without one. However, that largely depends on if you have the space for it! Mitre saws are greedy machines when it comes to gobbling up work space.
This is especially true of sliding mitre saws that occupy even more space thanks to their sliding-bar system. Of course, that's fine if you're in a large factory, but if your workspace is garage-sized, the chances are a sliding mitre saw will feel excessively space-hungry.
And that, right there, is why you need the Bosch GCM12, the "Optimus Prime" of sliding mitre saws.