I'm almost exactly like yourself. I used to play 4e, but then after a looong break, I got back in to Champions at the 6e level, and found some significant changes.
For me, biggest wrap-my-head-around-it change was the de-coupling of the PD, ED, SPD,REC, END, and STN stats from the STR, DEX, CON, and BOD stats. Other than that, which was more or less just a matter of bumping one's starting points up certain percentage, it was easy-peasy to "get with the times".