I've experienced both and recognise their differences. I will have periods of elation with the classic side symptoms. For example I will have very little sleep, do art from 8am to 8pm without a break, be easily agitated, etc, etc. I do not engage in risky behaviour though and don't have the delusions of grandeur that are hallmarks of all out mania. The main thing is that when I am hypomanic I have a self-awareness that doesn't exist with mania. I am able to recognise the state I am in and able to say I need help.