Both of the games have their quirks, but I would have to say Classic. Era requires money for so many things whether it's repairing weapons, putting gas in your car, buying a weapon, revival potion, etc. The methods of earning money are more fun and in larger variety than Classic, but to cover all the things I just mentioned you would have to play a lot to earn all that money. Classic really only requires money for houses and your appearance which isn't a necessity. Furthermore, everyone is on the same playing field for weapons strength.
Not trying to mimic Gun Gale here, but if lightsabers were easier to obtain, I would definitely play more. I liked using swords on Era and lightsabers (if I remember correctly) being able to deflect bullets give a fighting chance against guns. Yet, they are only available to the players who spend a good quantity of their time playing/winning events. The playerbase on Era is pretty immature for another thing. I wouldn't want to make friends on there. Every time I go on people are rude and especially gassy when they kill you. Classic's isn't perfect either, but I mean come on.
Era and Classic both have sparring arenas, but I really think Era's is a joke. Being put in that small arena with bullets flying in all directions. Maybe that would be fun if players were only given a simple handgun like a magnum or something. Again, I haven't played in awhile so I'm going by what I remember. These are just some of my main concerns with Era. I'm not taking Classic's side as I could care less since I left it and only come back for occasional visits.