I usually find the main page takes a long time to load up for me, but it is a pretty busy page (by busy I mean lots of pictures on it, not related to traffic). The searches can take a little while, but they aren't that bad (for me anyway), until I went to book a rewards ticket today, and just as I was confirming my connections, it went down for maintenance for 6 hours.

The downside of being an Aeroplan member who lives 12 hours time difference from YYZ, my peak booking time is their peak maintenance time.