Most companies I worked for used Champagne (flight planner 3000). IMO it beats Command hands down, and you can download a trial version on their website to see if it will run on a mac.
Software Download Centre
I could never justify the cost of purchasing such software, and after my CPL flight test never had to do a manual flight plan again.
Perhaps a suggestion is to manually flight plan for your big trip for a bit of practice and use the NAIPS app for iphone/ipad to submit your plans.