I use optimism.
When I'm depressed I use more of the features plus use the notes section. When I'm doing better I just fill out the sleep amounts and brief notes, when hypo I rarely remember it. It just has the numbers of hours slept and quality of sleep. I've noticed a direct correlation between the lack of sleep and an increase in symptoms, high and/or low. One thing I do wish it had is the ability to note the exact times I went to bed and kept on a schedule that could be charted, not just put in the note section. It just has the numbers of hours slept and quality of sleep.