I have never tried one in anger but I sometimes wear a suit designed for pilots that has a neck seal and wrist seals. I don't like the ones designed for cruise passengers with built in gloves that you have to put on as your aircraft descends towards the waves. As well as requiring time to put on when time may be very short I worry that they would restrict movement and make getting into a dingy difficult.
If you Google "aviation immersion suits" there are lots of options (and budgets).
I too would be interested in an expert opinion.