I have never seen a maximum share size either. I too have several very large shares with no performance problems. I would have assumed it would have been the NTFS maximum.
I have how ever, seen situations where the number of files in a single folder causes problems on windows when you try to view the folder in the gui and when you try to access (read or write) to the folder. My experience syats this definately happens at the 200,000 to 300,000 mark.
I to have never seen a problem with a large file share. I’ve got a couple of file shares with hundreds of Gigs of data in them. The key I think is the number of files in each folder. We keep the number of files per folder small (it’s an automated system so the files always go into dated folders) so we never really have a problem with slow performance.
We have on older share which has a lot of folders at the root of the share, and it takes a while to load up, but again we think it’s because of the number of objects. The sub folders all open very quickly when accessed.