Just like to speak my opinion on this:
- TDK was more realistic. TDKR was silly at times.
- TDK had better acting, Ledger was amazing.
- TDKR had little drama and too much action. TDK balanced it out well.
- TDKR felt ridiculous at times, a nuke, a prison underground, Batman sending cops to their death, etc.
- TDK was more down to Earth
That being said. Both still trump Batman Begins.