Barcelona I've done but wouldn't recommend it as no real race or after race atmosphere other than usual Barca stuff which you can do anytime.
Jerez I've done and was epic and the whole town goes bonkers with 200,000 visitors. Street parties for 3 nights, bars set up outside every shop and great weather.
Not sure about Aragon but maybe worth a try but need to stay with the race fans to get the most out of it.
__________________
.
|