I just fitted a pair of Continental RoadAttack 3 tyres to my 2013 GT. The bike had the original tyres still on when I bought it last September (bike had only covered 10000km) !
The difference between the original (worn out and old) tyres of course is massive. I expected that.
The new tyres I like very much. They give good stable feedback, and have installed a good confidence factor when I go out for a ride. After about 150km travelled on them, I had plenty of confidence to take both sides of the tyres to the edges. The feedback and stability seems to be the same regardless of my lean angle, this feature I find really great, so I can tip the bike into a corner with some safety margin, and if I feel like leaning a bit further over in the corner, its easy to adjust my angle and speed. The input to tip the bike over from upright, or increase the lean in the corner feels constant. Which gives me the confidence to take the tyres to the edge pretty quickly.
Straight line stability is great, but I would expect that from any new tyre setup front and rear.
So I'm very happy with the RoadAttack 3 tyres. I bought the normal version, standard fitment size, and not the GT version of the tyre.
I guess the tyre is a typical touring/street tyre. I can guide the bike from upright to the edge of the tyres with the same effort, the tyres are "round" in their profile, so the bike doesn't flop over into corners (triangular profile).
I have always found the steering of the GT to be stable, and these tyres keep that feeling. I've mainly been out riding in the dry so far, only once have I been caught out in the rain. In the rain I'm taking it steady anyway, and not pushing any tyres. In the rain the bike felt fine.
So all in all, I can easily recommend the RoadAttack 3. My type of riding is on open twisty roads in the countryside, and the tyres work great in this area. Maybe a more sporty tyre would give a quicker turn in due to a different type of profile (triangular), but I don't need that on the GT, and the turn in is great for having fun on twisty roads and leaning the bike right over with confidence. I feel I can ride the bike how I like in a corner, and the tyres do what I want, I'm not having to over compensate for turn in or anything like that, the handling is nice and stable and neutral, regardless of my lean.