I'm a 60/40 DC guy myself.
It's not so much the characters I prefer - both DC and Marvel have some fantastic characters - but the universe itself.
As for DC characters being overpowered and one-dimensional, they're really not. DC just constantly makes the mistake of pushing overpowered and 1D characters into the public consciousness, while letting characters who are actually really interesting, fly under the radar.
Wally West, Kyle Rayner, Tim Drake, Cassandra Cain, Ollie Queen, the whole JLI crew and more are all great characters, not particularly overpowered, but hardly known by non-DC readers.