I am not convinced by that node.
I know that Date::Manip has disadvantages and is not always the module to use, but I don't see why it's wrong here. I don't think this task needs high speed or full i18n. I do like Date::Manip for such quick tasks like this, because it's easy to use.
You say that the API is not consistent. There's only a handful of functions I have to use, and they aren't inconsistent IMO. (The functions are UnixDate, DateCalc, Date_Cmp, ParseDate, ParseDateDelta.) Having to use a few functions that can do almost anything (ok, I needed timezone conversion once) makes the module very easy to use which is more important than consistency in small and simple tasks like this.
You are right that the module docs say
If you're only doing fairly simple date
operations (parsing common date formats, finding the difference between
two dates, etc.), the other modules will almost certainly suffice.
but contrary to this I still find the module good for these tasks.