I think the percentages state that a suited hand has about a 5% edge over its unsuited clone. Like AKs vs AKo. However how important of a factor do you think this is in an actual game.

Let's say your UTG with AT at a full ring game. With a standard TAG style would you raise with this hand? Probably not, but what if it was suited. That's where the issue comes into play.

I'm sure there are many other situations where having a suited hand might compell you to play the hand more.