I am mac based as well, looking at target recruit which integrates with salesforce.
I reccomend Bigbiller www.bigbiller.com for several reasons.
1) its webbased so you can get on from anywhere
2) it is designed for recruiters first - its not a contact managment program that was modified
3) it's easy to use and and their customer service is personal and excellent.
4) last it's affordable...you pay on a monthly basis and it's way less then the others like sendouts or bullhorn
Give Todd Bossler a call there and see for yourself.
We are a small business, so our ATS needed to be affordable while giving us all the features necessary to be efficient and successful. I did extensive research to find the right ATS for us. We use Akken and love it! You can email me if you want more information on the features firstname.lastname@example.org or you can call them directly. Ask for Brad Thomassen 603.816.4009, email@example.com .
I wish you much success!