I like the Colwood Detailer and use the replaceable tips, no issues. It also survived a trip to Iraq with no issues.
For the cords, they offer 14, 16 and 18 gauge cords for thier pens to follow along with your style of burning. I have never had a problem with mine over heating the pen.
Colwood also uses Nichrome wire for their tips.
http://www.woodburning.com/toolshop/type.asp?iType=17
Another good thread for helping to decide (or confusing you even more)
Razertip or Colwood?
Good luck and happy burning.