What makes Counters attractive to me is that flexibility. You can count towards away from as many dates as you like, and these can be stay in the app or pinned as a colourful collection of live tile. Or you can set up a ticker counter for whatever reason - it might be repeats of a squat thrust in the gym, people attending a concert, or the number of times you hear the word 'allegedly' during an episode of 'Have I Got News For You'.
Now strictly speaking it has stepped out of the Windows Phone Design Language paradigm, but if you are going to break out of the box, you might as well break out with a lot of style. Huyn has done just that, with an interface that looks for taps, holds and swipes in the right hotspot areas to make it work. Thankfully the tutorial in how to find your way around is easily accessible and can be viewed more than once.
If you already use a counting live tile, Counters is worth evaluating. It's a free download via the AAWP App Directory.