"comfortable"

It is correctly pronounce [kVmf=r\4@b5=] "kum furt able". [kVmftr\=b5=] "kumf ter ble" sounds like dyslexia, reversing letters.

I pronounce it more like the second way. comf-ter-bull.

[k_hVmftr\=b5=] is the correct, and only General American pronunciation. The first way that you mentioned is neither correct, nor used by anyone.