The Ford ones are rubber while the poly ones are (as the name states) a harder polymer. I don't know for a fact but I would guess they are slightly harder but they can't be too bad or they wouldn't be so popular.
As per GG, poly bushes will be slightly harder then OEM stuff. Due to this, its probable they will transmit slightly more vibration/noise due to them being harder and therfore less absorbent of vibration (which is what noise is really)
Quite how much extra, I dont know. Id be too busy enjoying the better handling!