I found more info on CoinJar's fees. Where BTCMarkets has a link to their fee explanation page in each page footer, you have to go looking in the knowledge base to find CoinJar's. BTCMarkets wins points there for more accessible info.

The explanation of CoinJar's fees is spread across more than one page:
Understanding CoinJar's Fees
and
Bitcoin transaction ("mining") fees

The transaction/mining fee is the same as BTCMarkets' withdrawal fee: 0.0005BTC.