I recently upgraded from splunk 5 to 6. While everything seems to run okay when I view it from firefox, I discovered that my IE8 users don't have quite the same experience. While splunk6 works with IE8, the fonts used are less than optimal, rather light and hard to see. Back when I ran splunk 5, firefox and IE8 displayed the same splunk page with the same font. Most of our corporate users are still required to use IE8, so I may have to postpone the online upgrade.
(ps. I would have uploaded a screenshot example, but it was blocked. Something about karma???)