we went last year around this time, but we arrived the tuesday before. We went the 20th to the 27th (i think). The first part of the week was fine; no lines over 20 minutes really except for some of the fantasyland ones (ie peter pan). we don't have kids, so this was not a problem for us.
Once it got to be saturday it started to get a bit more crowded. It wasn't unbearable, but the waits were a bit longer. It is definitely better then going during the summer (june through august) in my opinion.
Hope this helps....