It will have to strain towards credibility given these points (a co-chair is Richard Muller, and the project manager is Elizabeth Muller, his daughter) but the work itself will be carried out by statisticians, computing experts, and climate scientists. BEST is quite a large umbrella from what I can see.
We can expect results from the project to be misrepresented, of course. I can state that with confidence because one product (Gilbert Compo's, IIRC) already has been, by the WSJ. You'll no doubt remember the thread about it.
Exxon gave, I think, $100m to Stanford and BP $500 million to Berkeley (don't quote me on the exact figures, though) for climate research, so the Koch involvement doesn't surprise me. These are mere (deductible) drops in the bucket and can be presented as proving an even-handed approach. For a mere few million they can have the research attacked very loudly later.
So best we wait and see

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