A definite for.
I have a pair that only come out when the thermometer hits - 3 or below.
I only use them on the beach,as at this time of year I spend most of my angling time chasing Cod.... and that means 8 or 10 hour night sessions on freezing sand or rocks,with the wind whistling around you,and sleet and icy rain coming horizontally. I bought a pair two years ago,and tbh I have never once been cold in them at all.
Just hoping for a break in the weather to get back on the river for a day.
If you do get a pair make sure that they are big enough to get comfortably on your feet, they can feel a bit tight at first.I only use one pair of normal socks with them,never felt the need for thick boot socks or anything else.
Hope this helps.
Dave