How much do you weigh, and what is the condition of the roads you ride on? The extra comfort of wider tires is the result of being able to run lower pressures while still preventing pinch flats. But there's some limit to how low you can go without increasing rolling resistance from excessively squishy tires. If your weight/road factors allow you to run as low as, say 85 psi safely, you'd probably get no advantage from fatter tires. I mean, a 32 mm tire might let you ride at 55 psi without pinch flats, but you probably wouldn't want to do that unless you were on sand roads or something like that.
On the other hand, if you're big, and/or your roads are really crappy, so you have to run your 25s at 110 psi to avoid pinch flats, you would benefit from bigger tires.
