The problem with Mandos can be summed up in three words.
Haters gonna hate.
Karen Traviss did not create the lightsaber-proof armor. She just used it. the Mandalorians are the focus of eight - count 'em, eight! - books. The Jedi, on the other hand, are stars of nigh to every other novel in the Saga. If a few novels don't focus on the Jedi but another culture - well, that culture must be mary sue-ish!!! Really? To each his own, I guess, but to me, the Mandos rock.