I have a rosewill Challenger for a recent build that I did. As of right now I plan on adding a coolermaster tx3 to it soon. While I was in there I wondered if it was worth it to replace or add any other fans. Right now the case is on a hard surface in the open, however at some point it will end up being enclosed in a desk so I want to do as much as I can now to get cooling taken care of.
More aboutworth swaping case fans
Not generally worth it unless you know that you will have heat issues. Use the stock fans for now but close the case up and make sure your temps are good.