Sadly, while the proc is cool, I wouldn't equip the Commendation of Quel'thalas at 80 unless I hadn't gotten a level 80 trinket. I'd love to see a trinket like that, upgraded for 80 from the new content in Icecrown. =)
I have found the commendation proc highly useful. Although I only have on my DK, but that is because my warrior got black heart first.