Have been using lighting for well over a year, primarily to (no surprise here) access google calendar. Through the gcal provider or caldav, it has had problems dealing with google calendar event reminders. Recently installed Thunderbird 3.1, with latest lighting build. Still had the annoying inability to deal with event reminders from google calendar.
Now I simply use gcalcli. In conjunction with todo.sh I have an email of my agenda in my inbox each morning. Lightning is permanently removed from the picture, and I still get my appointment view and todo list with one click in the email client. Further, gcalcli reminds me of events flawlessly. Why gcalcli can do it in ~1000 lines of python and lighting cannot, I dunno.