Thanks for covering this. It appears other tech blogs such as Phoronix like to ignore Vivante, but their market share has increased a lot over the last year, mainly thanks to Freescale and Huawei.
I'm a bit sad that my blog post on GC2000 OpenCL is being used to bash Vivante. Many of the problems I encountered were due to drivers, not hardware limitations. They were still taming LLVM at the time. And you simply cannot expect the same performance and features from a mid-range embedded project as from desktop. There are very different power and area constraints. No one has done Mobile OpenCL right yet.
At least the Vivante GPUs have a straightforward, scalable, even desktop-like architecture. See Rob Clark's XDC slides http://www.x.org/wiki/Events/XDC2013/XDC2013RobClarkARMOpenSource/soc-graphics-update.pdf , Not a bag of hacks such as PVR (which look good in benchmarks but are a hell to work with), so there is hope of better drivers being developed, either the open source drivers we're working on, or through improvements in Vivante their own drivers.