I don't use an alarm clock, I just go to bed early and wake up in time...
But in periods when I've really had trouble with getting up, the core problem hasn't been physically awakening my brain, it's been that as soon as I woke up I knew there was just boring miserable shit all day to look forward to, so I was likely to just snooze.
In those periods, I discovered that the only effective way to get my brain going enough to understand the rational course of action (getting up & showered), was to have something fun within reach -- my computer, usually.
So I'd wake up at the first ring of my phone alarm, then flip up my laptop and read some Reddit or whatever.
If I really needed an exceptionally effective alarm clock, I'd want something that maybe starts talking for five minutes about something interesting, or prompts me with some captivating question, or shows me a gallery of cool pictures, or something.