I play both. 10-max at 600/1000 NL is still somewhat a camping game, but 6-max at 600/1000 NL is anything but a camping game.

In 10-max you can sit there and fold almost every hand you see and wait for good hands to raise with and slowly take money off of people. At least this is what I do. Not as much bluffing happens in 10-max, since people tend to have better hands on average and its harder to bluff them out.

In 6-max however, the average hand is much weaker and bluffing is very important. My play ultimately depends on the other players at the table. If the table is too tight and conservative I raise the hell out of them and keep stealing pots and blinds. If its too aggressive, then I set a gazillion bear traps on people and keep getting paid off by playing ultra passive. Knowing what players you are up against is much more important in 6-max.

So in short, 6-max in my opinion involves a LOT more skill and imagination than 10-max where you can get by with playing ABC cookie-cutter poker.