Just curious, Sky King, what do you mean by better quality?

FWIW, I've tried to read the research from Bicycling Quarterly (edited by Jan Heine) but it just makes my eyes glaze over. Also from what I've seen they don't seem to really be targeting folks with racing style road bikes. I know someone who buys tires based on their recommendations -- much wider than would fit on my bike -- and he loves them because they give a super smooth ride. But they're also so thin that they puncture if you just look at them funny. Personally I'd rather have road buzz with a tire that is more puncture resistant. But that's me, obviously my friend has a different preference.

On my bike (Trek Madone), 25mm tires are the widest that can be used. I would look into 28s if they would work but until I get a different bike they're not an option. I think the main thing with 23s vs 25s is that the 23s don't offer any advantage for racing, not that they are a significantly worse choice. Though I'm no expert on tires so I could be wrong.

One thing I've noticed with the Conti Grand Prix 25s is that they are a bit wider than the Mavic tires were, and possibly also a bit wider than the Gatorskins I used to use. When I take the front wheel off, the Grand Prix tires don't clear the brake pads freely, I have to push the tire through them. I've never had this issue before putting these tires on my bike. I had read that different brands of tire can vary in their actual dimensions even when they are labeled the same size, and apparently I now have real world evidence of this. It's not a real problem, though, at least not for my bike.