It's a bit of a pain, but quite doable on most distros, if you know your way around. I just did it on two distros for my ThinkPad 25: with openSUSE it was part of a weekend of playing around with it and setting it up, and on NixOS it took an hour or two to set up how I like.

The real problem, imo, is that all of the solutions work badly (they either work at a performance penalty (as with Bumblebee) or require a separate X server for each GPU).

This is entirely a result of NVIDIA's refusal to implement decent support. The Nouveau drivers offer proper PRIME support, which yields an experience more like that on Windows in terms of workflow and the amount of setup (virtually none) required, but they have their own performance problems. Hybrid graphics with AMD GPUs apparently works nicely with whatever drivers you like, granted that the software stack is sufficiently up to date on your system.

I didnt bother - I set it up to only use the Intel GPU b/c I wanted longer battery life. Besides I don't game on the laptop anyway. I dual boot Windows (since the license came with the box) and can use that if I really want to game.

However if you really want to, everything pxc says below is spot on...