They were up and down with both. There were quite a few times, even with Manning, that they only made it to the playoffs because the division was weak and were bounced out of the playoffs just as fast.
I don't think Peyton Manning, in his prime, could lead today's Colts to a playoff run. Well, maybe he would get them a Wild Card at best.
Also, I like Andrew Luck, but I have to agree with the sentiment that he's probably close to done. He's spent like half his career on IR. Really a shame, someone with his much talent and potential doesn't deserve this.