Firefox has been good to me for many years, and still is.
Chrome is okay for certain, simple things, but lacks too many features and too much accessibility. While faster and sleeker, there is no denying it’s common roots with Safari, including the attitude that including the things that serious users need would make the browser “too complicated” and are thus omitted, making it more painful to use than it’s worth.
Internet Exploiter has one trait that makes me keep it even though I rarely use it; AcitveX. In fact, ActoveX is why I rarely use it. However, there really is no other way to get those Windows updates that the system doesn’t automatically grab itself.
As for a non-Apple program/system having issues after upgrading Apple software, there is a reason why I trust Apple’s PC stuff slithgly less than I trust IE. Now @rosehips knows why ;)