vmware fusion, parallels, or virtualbox?

is vmware fusion/parallels worth it? or can I do 95% of what they do with virtualbox?

recently bought a '12 MBA and would like to put a vm box together running ubuntu for some dev work in linux. any recommendations? i've heard/read that parallels really screws you on the yearly upgrades (or the lack of updates for OS support).. what do you guys think?