Should I prefer an AMD or Nvidia GPU for studying graphics programming, especially with respect to vendor specific debugging tools and ecosystem? My current laptop has a fairly old Intel integrated GPU which was good enough for following simple tutorials.

I am now keen on getting to grips with advanced techniques and newer APIs, and so I am looking for a new discrete GPU.

I want to ignore the usual price/performance metric for GPUs, as I assume that's going to be irrelevant for a hobbyist programmer.

Is there a pragmatic reason to prefer AMD over Nvidia or vice versa?

A cursory search shows that some tools are exclusive to one vendor (e.g. Nvidia Nsight), but is one significantly better than the other or are the differences minor?

Will drivers make a difference here also? And finally will I run into a lot of example code specific to one vendor?
If you want to learn OpenGL X.Y or DirectX A.B then shop for hardware that supports that specification. 

If you're using other software (Blender, Maya, 3DSMax, etc) you'll want to make sure it's supported.

If your OS has a history of issues with a particular vendor, adjust accordingly.

Beyond that, it's not going to matter much, especially at the hobbyist level.
Price / performance metrics are still relevant, it's just that the definition of performance is different.