Diablo CAM the best CAM without doubt in terms of what it opens.
Keep an eye out for the forthcoming ABRACADABRA CAM (if it ever arrives) as its from the ALI/ABRACADABRA/MORESAT teams and opens (or promises to) more than Diablo (eg Orbit, Canal France, ART/Showtime as well as the packages/channels opened on Diablo).
Don't ignore some of the older (supposedly dead) CAMs eg the long living Dragon/T-Rex/Matrix(Magic same family as Matrix) CAMs with a little program called fausto and a season interface/dummy card you can get into Card Sharing cheaper than the Diablo route and read Control Words from any official cards you have.
And I know its outside the polls section, but I've added a poll so townni can get a better idea of Sat-Universe's general consensus.