I was in Currys a few days ago, hoped to be able to try the 3, I do have a quest 2, but all on display were non working copies of both headsets.
Looking at them side by side though the 3 headset itself is a lot thinner (40% I believe) than the 2, but taking what seemed a larger facial interface into consideration, the difference didn't seem that great maybe an inch or so.
So as the 3 is a little heavier than the 2, my instincts were, that it probably doesn't feel a great deal more comfortable than the 2 but as couldn't try it on I was none the wiser.
Meta's prices seem to be all over the place though, When I bought the 2 it was £299 a few months later it went up to £399, now on sale for £250, so given time and when eventually they phase the 2 out, I can see the 3 dropping in price, well hoping anyways.