"Old" vs. "Heroic Edition" Game Client
Unless you want to play two accounts it is not worth it. You can buy the armor and a bag for much less than a full game.
There is no difference in the client or how the game plays.
The only differences between the Original client and the Heroic version is the name, unless you are speaking about the Digital Deluxe version.
The original Digital versions had the Hero’s Band (for pre-purchase only). The new Digital Heroic version comes with:
Choice of -
Krytan Armor Chest or Primeval Armor Chest or Profane Armor Chest
18 Slot Mithril Box
10 Experience Boosters
All of the above can be purchased in the Gem Store or Trading Post.
The Golem Banker now lasts 2 weeks, rather than 5 days.
You can purchase an upgrade in the Gem Store; it was recently on sale for 1000 Gems, and may still be so.