I've worked with CUDA, and his negative conclusions are a little too dramatic compared to how elegantly he used CUDA. (That said, the biggest cost of CUDA development is the year or so it takes to let it all sink in. ALL of it!)
As for my negative conclusions... I wouldn't describe them as "negative", just "objective". Some algorithms are easily adapted to CUDA, and you get an easy win of 10-40x. Others need a lot more work to offer speed gains, and finally, there are some that are simply hopeless (you have to redesign them from scratch).