Huge difference. I have a RIS where I've "always" boiled it for about 5 hours. Last time i did som math to target 60 minute boil time. (I've also done it at three hours and something between 3-5 hrs, but not very often, most often it's been 5 hrs) Very different beers, like completely. The 5 hr boil is smooth as slik and thick as oil, the 60 minute is thinner and not as silk-smooth, but more easy drinking, equally enjoyable, but just different. Here's the kicker. The OG and FG for both (all of the 5hrs boils, comparing to the one 60min) beers were the same.
I can also tell it in Doppelbocks where I've boiled 3 hrs vs 90 minutes, and hefeweizens where I've boiled three, two, one and a half (slightly different) vs 60 minutes. They have all been boiled at the same boil intensity.
Boil intensity matters also a lot also. I can tell difference between hard boil 60 minute and slight boil 60 minute. the slight boil 60 minute has a good full mouthfeel which doesn't come from viscosity, but rather from uncoagulated body-positive proteins, but also some sort of "thinner" feel at the same time, almost like it's drier. Hard boil 60 minute is thicker due to viscosity.