It isn't that it doesn't work - it is that it doesn't have features I personally depend on as standard (and it is the stock app to my knowledge). On one example, I put my uni timetable in to my phone at the start of the semester and have the events reoccur weekly at the same time. On my Nokia it had the very simple field of 'repeat until' below the option to select 'weekly', on Android, it just repeats until the end of time. Now there is the option to then go and delete the events, so instead of just setting an end date, I have to go to that date and then delete 'this and future events'. Now that would almost be okay, but I also have a mid semester break, one week where those subjects don't run - so you'd think I could delete them for that one occurance - nope, I could delete the entire series including the past weeks, or just that one and all future ones. The only thing I could do was just remove the reminder and ignore them popping up.
It isn't a 'big' thing, but that's precisely the point, what is only the addition of two options would expand greatly the flexibility of the defaults. As it stands the only other way would have been to have a Google synced calendar and set up the events online - while I haven't tried it, I'm told you do have those options there.
Little tiny issues like this are what I'm running in to across Android, which is a shame considering how much of it I like.