I do them since I do them as my 3rd or fourth back exercise and weighing 230 and doing them wide grip style I don't go above 210 with pulldowns for strict reps though. I rather do these strict then throw my wieght around doing chins. However, once I lean out and get my weight around 215 or so I will go back to doing chins again.
I do lat pulldowns and i think they're one of my best lifts... chins seem to be too easy even when i add weight.... lat pulldowns really blow my lats up like nothing else that i do...those combined with T-Bars and i cant seem to put my arms down on back days