Pros:
• minimal interface: one window, one list, one pulldown
• dock icon shows current timer in hours:minutes
• interface with Invoice 3 (I haven't laid down the €79 to try it, but I may when it comes time to make an invoice)

Cons:
• keyboard shortcuts are nonexistent
• timer covers tasks list. You must stop the timer to interact with the tasks. Or in truth, you can interact with them through the black veil, but that doesn't count

The compromises are in favor of the employer, though they amount to only seconds lost. It kinda seems fair that clients shouldn't be billed while I'm fiddling with a list of tasks for their project. At least that fiddling is still pretty quick. I can stop a timer, choose a different project from the pulldown, choose a task, and start a new timer in about two seconds. I just wish that I could add tasks, navigate and close inspectors, and start the timer with keyboard shortcuts.

Compared to other simple timer apps going for about US$40, this is much better, and while it's free, I have yet to find anything to match it.