We had a pretty good time but only because:
a) we knew it was going to be crowded
b) we have been to WDW lots of times
c) we were able to prioritize what we wanted to do
On Sunday we ping-ponged between DHS and Epcot and, with severely lowered expectations, ended up having a relatively good time, though did not actually do a lot of rides/attractions.
Didn't start out too well though. Got to DHS just after opening and TSM standby was already at 50 minutes (usually more like 30 at that time).
Went to Epcot and had a nice breakfast at the Land and got FP's after breakfast for TT (our main goal for Epcot that day as they were all gone when we got there Saturday later afternoon).
Went back to DHS and spent the afternoon doing rides (just 2 - TSM and StarTours with a FP) and shows.
Then left for Epcot to finish the day with our ride on the new TT. There was a line out the door for FP holders but it moved fairly quickly.
Just a note: when we returned to TSM for our FP time there was a line out the door and down past the FP kiosks for FP holders. The line for standby was very short but the wait time for standby was 3 hours. The CM said they were letting in about 40 FP holders for every 4 standby