Ha, I work for BigCo, and we use Kronos for timesheets. We recently transitioned to win7 (from XP), and to get Kronos working again we have to run some virtualization app (citrix maybe? can't remember right now, definitely a vmware product though) to run IE8 and some obsolete java version. All for timesheets.

Other than that it's pretty useable. At least compared to SAP, which is my only other timesheeting-experience.