Never had a problem with either EZCD or Nero. EZCD's interface is more polished, however functionally there is little difference between them. The biggest difference I've seen is that OEM copies of EZCD will work with any CDR/W drive, while OEM copies of Nero will only work with drives of the same brand that the OEM copy came with. Which is a moot point for someone buying the retail package.
And for both packages, the recording and editing applets that come with them are suitable for newbies or casual users only. Anyone who cares what their recordings sound like would use better tools like Cool Edit Pro or Sound Forge.
IMO choosing between EZCD and Nero boils down to a matter of cost - retail package Nero costs $50, EZCD costs $80. So Nero has the advantage there. I also think that's why you are seeing more burners come packaged with Nero - I'm sure it saves the burner company money, and has nothing to do with the relative merits of each actual program.