Weekends are busier than weekdays usually because the locals go to SW.
But it is nothing like Disney. You really don't end up in a lot of lines because most shows are in huge stadiums. If riding the coasters get there early or ride close to closing and lines won't be as bad. starting May 22 the new coaster will open so I expect bigger crowds in the park for that. It looks awesome! Watch the schedule to see if Shamu Rocks is showing and how late the park will be open.