i think it would be easier for me to write a list of mando's a disliked or were my least favorite than to say who my favorite is!
i like lots of mando's! i would never have gotten into them had it not been for boba and jango. i currently costume as a'den skirata. although only in the books for a short time, i really liked the character. before him, i costumed as jaing. i just thought he was too cool in the lotf books... the way he punked mirta and out-bested the best, boba. i really enjoy kal as a character. i never played the kotor games akthough i know the jist of the stories. so i don't know alot about canderous. cassus fett and mandalore the ultimate look great but, i've read the first 5 volumes of the kotor comics and there hasnt been alot of charater develop in them yet. rohlan dyre is a great character.
some notibles not on the list:
goran beviin. boba's right hand man. etallic blue armor, beskad and crushgaunts! as if he weren't cool enough in the lotf books, read a practical man where he cracks the crab shell!
baltan carid: white and violet armor, crushgaunts than crushed darth cadeous' leg and he kneecapped the sob!
ram zerimar: started life as a custom mando costumer. karen traviss loved his look and mando'karla-ness that she befriended him and made him a canon character!http://blogs.starwars.com/Mando-ramser/44http://starwars.wikia.com/wiki/Ram_zerimar
beviin verhayc: a close friend of mine with a similar story to ram. he and his gf, mirgo ruus, were canonized at the end of order 66. not alot has been written of them in the books but, i believe they have wiki pages with their fanon stories.http://mercs.firespray.net/forum/index.php?topic=1002.0
(hopefully that's public viewable!)http://starwars.wikia.com/wiki/Beviin_Verhayc
mandalore the indomitable: based on looks alone, this guy is an 11! granted he's really only appeared in the sith wars comic that are over a decade old. the stories and artwork themselves weren't bad but weren't thegreatest. he was a man of his word, loyal and lived for the war!
if you want to see a handful of great "custom" mandos check these out...http://mercs.firespray.net/wiki/index.php?title=Main_Page
while none individually have been "canonized" in any any books etc., the group is an LFL authorized group. so technically, although not individually canonized, they are as a group canonized as mandalorian mercs!