Having tried many times to use local time instead of UTC to make life simpler for myself, I really don't think it's ever a good idea.

Better to localize times for users on the client-side based on their local settings, IMHO

For quotas and usage limit resets it can be a little harder, but if it's a cron job anyway, my initial approach would be to just schedule it for a time that is close to midnight for the area your customers are in.