If you're careful putting on CLP/CLU then you won't have any problems. you need to do it properly with a cotton swab or something, rather than putting a blob in the middle and letting the IHS spread it out.
If you do it like that, you won't have any problems.
I personally prefer non conductive TIM. I killed my i5 3570k with CLP once, not gonna risk using it on cpu die again. Not because the TIM is bad or anything, just in case I do another sloppy job in spreading the TIM.