I own a Daystate Huntsman Regal in .22, I owned a AA 500 .177, my Daystate is still my most accurate PCP.I never could get the AA to match my Daystates accuracy.
I don't think you could go wrong with either one. Honestly, I think it's just the one that creates the most enthusiasm in you. Beside that, if you had the opportunity to shoot before buying would be great. But I don't think you could be disappointed either way.
I own neither but they are both good. Since you said you first posted this in the FT forum I will say I see more AA500 rifles being shot in FT. If it was my money I would buy the Daystate as that is the best looking air rifle ever made. One day I will own one.
Another thing I've found about the non-electronic Daystates I have owned...they aren't particularly friendly to change power levels on. They tend to have preload spacers for the hammer springs, etc. Really a "take out of the box and shoot it" gun, in my opinion.