I thought IE supported :hover on other elements since IE7 or something?
The element occasionally remains in the hover state if the cursor is moved from the element while the mouse button is pressed; the hover state sometimes fails to apply when it should.
:hover doesn’t match elements with negative z-index property values.
:hover on elements other than anchors is often slow to react. On large tables this can prove to be almost unusable. A fix is to add position relative (assuming the element is not positioned) to the element being hovered.
In Internet Explorer version 8, the manipulation of elements with negative z-index is buggy when used in conjunction with :hover or :active rules
Also only works when using certain doc types. XHTML Strict only for example is one. Buggy as hell when using HTML5 doctype.