Just ordered one from Abe's today for $369 shipped (after $100 mail in + code: LOYALTY15). How's the focus ring on it? I played with a friend's 17-50mm and it had a gritty/crunchy feel to it. Is this normal for Tamron lenses? Also, is the auto focus really as slow as some reviews say it is? I like the insect shots and was wondering if this is possible to achieve using autofocus.