I like going to one site and being able to find all the info I need/want.
Things I use the most are "My Sets" inventory, and looking for pictures of new/upcoming sets.
I work at the Lego Store in the Houston Galleria Mall and I refer people to your site all the time. We as employees use your site all the time. It is hard sometimes to find retired sets on the Official Lego Page. So when people come in looking for a specific set number, we go to your site.
The Official Lego Site is pretty easy to use when looking for instructions; however I still find myself coming to Brickset and clicking the link, probably out od habit.
Y'all do a great job of posting new sets pictures and numbers as soon as the info is out there on the net. Yet you respect the Lego Co. enough to take them down or not link to them if you know they were obtained illegally.