Hi griff,
If you're getting good performance then I'd recommend just sticking with it. Internet Explorer is a general use browser, so it tends to have generally decent performance overall. Google Chrome & Firefox are just a tad more efficient for gaming and certain types of web-applications (flash being one of those applications).
Your login credentials won't change, so if you try a different browser the same username/password will work. Chances are the new installation of Chrome wasn't defaulted to accept cookies and that's why you were having issues logging in. There is also a separate flash plugin used for IE than for the other 2. You may not have the flash plugin for Chrome installed and that could cause an issue too.
My best advice is if isn't broke don't fix it. =)