At any case, I hired him fairly recently for a security audit and he worked quickly, and was very effective (he found several important vulnerabilities and reported them in a crystal clear manner). He was also a pleasure to deal with (no bullshit stance, something I find enjoyable).
The 4000 USD for ~20 hours of work were definitely well spent!
Wouldn't it also be wise to keep people like him 'out of the loop', I imagine it's much harder to audit when they have access to internal code/architecture that would be difficult for an outsider to stumble-upon?
