I know the Blaze has an adjustable framesheet, so it is easier to get the fit dialed in than on the Crown. The Crown either fits you or it doesn't, which has been a problem for some people around here (although mine fits and I love it).
The Crown sports a roll top closure where the Blaze has a drawstring closure with criss-crossing buckles, so this is probably personal preference.
I really like the modularity of the Crown (removing the framesheet for lighter loads). The GG website states that both packs are good up to 35 lbs, but I'm assuming the Blaze would perform better at that weight due to the stiffer framesheet.
I'd say if you see yourself carrying 30+ lbs often and need the adjustable torso sizing, the Blaze would be a better choice. If you're below the 30ish lb mark and can fit one of the fixed torso sizes, go with the Crown. Both are fantastic packs. Good luck!