Originally Posted by
syntraveller89
I plan to just get a IC card for the days inside tokyo but which should I get Suica or Pasmo?
No difference in the Tokyo area. Historically, Suica has better interoperability with other areas in Japan, so you may find it more useful for local transport in the other areas where you plan to visit (for transport on lines other than JR). I don't know if this still holds true, but for that reason alone, I'd go with Suica just in case.
or should I just get the 14 day pass? The difference is JPY 17,280 and I don't think I'll spend that much on train trips within tokyo for 6 days.
You're unlikely to use that much on local trains in 6 days. Also, if you tried to use the pass, you'd find yourself limited to JR lines. There are dozens of other lines in Tokyo that are not JR and thus not covered by the JR Pass. It's better to be able to choose the route that's best in terms of time and convenience.