It's WAY too early to call this. If it came out today and I had to buy one, I'd get a PS4. Used game blocking is a deal breaker. I don't care how amazing it is, it's a complete deal breaker.
Now, I fully expect major third parties to block used games on the PS4, but since we haven't heard anything else, I'd go PS4.
PS4 blocks games? 3DS/PC only.