I was under the impression that AMD's strongest R&D in the past few years has been directed at hybrid consumer desktops, surely this should translate directly into their server processing products.
Meanwhile NVIDIA also seems to have really good marketing behind their GPU software stack. Lots of people who use CUDA have no idea that OpenCL exists and no idea that porting between CUDA and OCL is not super difficult. (It's been years since I've looked at CUDA it might have diverged more significantly since).
AMD's stability (on linux at least) is pretty poor. I don't know if it hurts adoption much, but it can't help.
Also, AMD absolutely dominates on integer workloads which is why it had been used so much for cryptocoin hashing machines prior to the widespread availability of ASICs for most algorithms. On floating point workloads, NVIDIA might do better than AMD, and those seem much more common in science than integer math.
Have you had any concrete issues recently? This may be one of these things where public perception changes slowly, unfortunately.
I believe that they may be improving, but in general I have seen far fewer functionality problems from NVIDIA than AMD. Generation after generation, it seems to replay itself.
I get the distinct impression that Nvidia try hard to make things work easily for you, whilst AMD just do not care (at least for Linux).
Relatedly, AMD's website has an 'OpenCL Optimization Guide' [0] (which you really need in order to use your GPU effectively) - for 2 years now, it has been out of date by 1 year or more, not updated to discuss the latest hardware.
[0] http://developer.amd.com/tools-and-sdks/opencl-zone/amd-acce...
Things have not changed since then.
Here is the author of the book "OpenCL in Action" discussing his problems with AMD's drivers: http://www.openclblog.com/2014/10/amd-and-opencl-20.html
Best quote: "dealing with fglrx is murder. I have never installed an AMD graphics driver without repeated trial and error."
My own impression (using AMD consumer cards for OpenCL on Linux) is that AMD just do not give a damn - their documentation is way out of date, their support in the forums is poor/nonexistent, their installers are just broken most of the time, etc etc.
You mean their APUs? They're taking the worst of both worlds (AMD CPUs and integrated graphics) and selling them as a package. They're pointless, imo...