I totally agree on the overlapping issue. I had to fudge my schedule a bit to accomidate for overlapping items.
Also, I did not like how you could not see what other sessions were going on during a time period if you already had something scheduled during that time period. You had to actually remove it from you schedule before you could look at the other sessions that were taking place during that same block of time.
I had overlapping content in my schedule. Granted I've since dropped one of the overlapping sessions but they did overlap.