I use it. I honestly don't recommend it; it's poorly written... it has a few minor bugs (for example, it won't let me cancel a new item when i press cancel, it just leaves a new item). Performance is kind of sluggish for this kind of app. It is however, a useful tool if you need to setup reminders or quick one click timers. I haven't found anything remarkably similar yet.... I remember I saw one a long time ago but couldn't remember what it was called. Anyway, it's only $1 though. Give it a try. I use this to remind me how long ago did I do something... eg: haircut, workout my abs, cardio, etc
here's a new app that might be doing the same thing, with a little bit more customization that I stumbled upon, iBeer Timer http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=295172291&mt=8
Wow it's free. I should have check this out before purchasing LifeTimer. It seems to having a nicer UI than LifeTimer.