I definitely think it’s worth it IF you can arrive before 11:30am or if you were planning to arrive after 3pm and only stay for a few hours. If you were planning to arrive between 11:30am-3pm, during busy season, I’m not so sure.
We visited Blizzard Beach last week during Spring Break. We flew in late one night so we stayed at a hotel by the airport. The next day we were checking in to All Star Music. Since we arrived the night before, we were able to get to Blizzard Beach right when it opened at 10am on our resort check-in day. It was busy from 11:30am-3pm. Not uncomfortably crowded, but people arriving during that time had a really hard time finding chairs and you could see the long lines for the slides. Our kids, 6 & 8 were more into the lazy river and wave pool so the lines for the slides didn’t bother us. We would have liked to ride the ski lift, but the line was too long all day. We had a great time and stayed until about 3:30pm, we probably would have stayed longer had we not had dinner reservations.