You know, I actually collect both now. The primary difference I've picked up on is that with pre-war, the cards are a beast in their own right, beautiful, and aesthetically amazing, eloquently artful, and overall - freaking awesome!
The new stuff, I collect but I'll never drop the money that I would for pre-war; no way. In fact, I had mentioned on another board that my ratio of spending is 10 to 1 = pre-war vs modern. I don't mind getting burned on the modern stuff - it's only a few bucks. I'd get pissed if I got burned on pre-war and forums like this have been great educationally to learn real vs fake and good history lessons.
And it helps with the fact that I refuse to sell my cards - all for my personal, greedy enjoyment!
