It's pretty rare my phone makes it 24 hours without being soft reset at least once. I always check it and hope I see it over one day of uptime. Last night I almost made it -- 23 hours and some change. Started up Skyfire to watch a show off Hulu before going to sleep, but it wouldn't load. Oh well, I still had SprintTV. Started that, worked fine, the "Press the center button to keep watching" after 5 minutes came up, but my center button wouldn't respond, nor were any of the hardware keys. My video stopped, I got frustrated and tried to get the hardware keys to work, but they wouldn't. At like 23 hours and 45 minutes I soft reset it to get the keys working again.

Generally, I end up soft resetting it because I'm making changes to it, or something freezes. I haven't been experiencing the call issues you say you have.