I haven't tried the sealskinz, but have used the Unger ones for years (or did at any arate)
And they do make your hands stink like gone off pee after a while.
Make sure the gloves are nice and warm when you put your hands in them, also make sure your own hands are warm too, make sure the circulation is flowing well and your hands are glowing!
This way your hands stay warm and insulated, put them in cold and you'll struggle to get them warm.
Actually that applies to all the gloves in fairness.
The Unger ones are not hard wearing enough for WFP, they get pinched and rip easily, don't know about the sealskinz, but if they are neoprene, they'll be the same.
Last year Omnipole got hold of some gloves that are used by fishermen, fur lined and very hard wearing!
Trad users might find them bulky and cumbersome (I don't though) but for WFP they work very well indeed.
They are about £20 or so, or were last year.
Regards,
Ian