I have been using Gmail for some days now, and there are some things that bug me:
You can’t mark all messages in the current folder as read. (All actions only work for the current page.)
You can’t search using regular expressions.
You can’t add mail addresses in
Cc:to the address book automatically.
Else, Gmail works really fine for me. I have been reading
with it for some days now, and find the threading support very useful.