The fan switch could be in part due to problems they had with the TMD fans not working properly. YS blamed the problem on Vantec, saying the screws attaching the fan to the HS were too tight or something, and as a result, a short could be caused inside the fan.
This happened to me, actually... had a tough time trying to figure out why my Aeroflow would work in my hand, but not on my CPU. Apparently sitting on the CPU grounded the fan and caused it not to spin up. A trip back to the shop and a new Aeroflow fixed the problem, but I've been a little worried ever since.
Hopefully the new aeroflow will be a good performer. My original aeroflow is still working great, alot better than the thermaltake volcano 6cu it replaced. Unfortunately the TMD fan seems to be pretty loud, maybe the new one will address that as well.