I just got an E-mail from Adorama. Mine should be here next Monday (Sep 17th). Ordered on July 14th. I think I have a buyer already for my "old 500". It's been my most used lens and one I couldn't do without. Hopping for good things with the new one!!!!
I don't know about availability, but I'm loving mine. Have been out photographing the wild horses a few times. It's noticeably sharper than "old 500". I do have issues with the design of the tripod foot. The balance is wrong for me when using it on my video head. Curious if anyone else has seen this. I haven't read anything about it in any of the reviews.