Actually, no, they're very effective on whitetails out to about 200 yards, provided they're fed good soft-point ammunition. And they'll work in darn near any weather conditions, which makes 'em very popular up here.
I made a trade a few months ago that netted one. Didn't really want it but it essentially came for free. Figured on just trading it off later. Maybe I'll have to give it a second look.