They tend to tick-tock between Nvidia and AMD. Although this update is once again an AMD (Mid 2015 is AMD as well).

My late 2013 was Nvidia.

> They tend to tick-tock between Nvidia and AMD

I'm not sure "tick tock" is the right word. The MBP used AMD in 2006, NVidia from 2007 to 2010, AMD in 2011, NVidia from 2012 to 2014, and 2015 is AMD. It's actually a break in the pattern for them to use AMD chips two years in a row.

My understanding was this generation of nvidia GPUs is a pretty solid step above the AMD offering.

They are using AMD's latest polaris generation GPU's which are $/perf/W on par with Nvidia, just don't have any super-high end offerings (GTX 1070 and GTX 1080 are unrivaled)

> They used to have Nvidia gpus as an option (mine is, from 2014).

And the laptops tended to die because of that (mine is, from 2010)