Regarding how they feel, I couldn't tell you by feel whether I have 25mm or 28mm at the same pressure. The 25mm will have slightly lower air resistance drag (high speed). In theory the 28mm may have slightly lower rolling resistance, assuming that pressure and other tire qualities are equal.

We can generally run the wider tire at lower pressure without risking pinch flats, as opposed to dropping the pressure in narrower tires which risks pinch flats. That's the advantage in ride quality, the lower pressure. If you tend to pump the tires up pretty hard, there is no real difference.