I am also experiencing these issues. I've heard this issue is usually limited to big and/or old accounts. I've had my Google account since it was in Beta, and i

I am also experiencing these issues. I've heard this issue is usually limited to big and/or old accounts. I've had my Google account since it was in Beta, and it's 48% filled. Gmail has been so unbearably slow for me that it forced me to switch from Firefox to Chrome on a Mac. In Chrome, it's much better, but still very slow. In fact, I just got Office 2011 and trying out Outlook.. I've used to be a devoted Outlook user before I switched to a Mac and went 100% Gmail for all my personal & professional mail. But Outlook 2011 for OS X seems awesome so far, so maybe this will be the end for my Gmail experience.