I opened it it up and waited the customary 5 seconds while it loaded the page.
And then I had thought.
I've always assumed that those 5 seconds were the various bits of html and javascript downloading. It had never occurred to me that it might also be the running of the code that takes time.
So I grabbed Chrome - which is much faster with Javascript - and installed it (which took about 2 minutes in total) and opened up GMail.
Almost instant.
I'd been blaming the internet pipes/servers for the loading speed, and actually it's the speed of the browser.
Of course, right there on the page there was a large advert - and the tabs don't work "right". So I'm not going to use it much.
But I was impressed by the speed - and I'll be looking forward to either Firefox catching up or Chrome getting extensions.