I'm sorely tempted by the Castelli Diluvio Deluxe gloves, particularly because they extend up past your jersey/jacket cuff so rain water doesn't run off the jacket and straight down inside the glove, as happens with me at the moment. But I just can't bring myself to fork out £35-40 for them. Essentially they are 3mm neoprene gloves and loads of other people make these much cheaper. Surfing companies have loads of options. Such as these: http://www.wetsuitcentre.co.uk/alder_4mm_spirit_dl_wetsuit_glove which are thicker and half the price.
I understand from reviews that these don't keep hands completely dry, but they still do an excellent job of keeping them warm, which is fine by me. I'm not really bothered if they are wet so long as they are toasty warm on cold days.
Does anyone have any experience firstly of neoprene gloves, and their effectiveness of keeping hands warm when it's zero degrees, windy and wet outside? And secondly, more to the point, has anyone successfully used other cheaper neoprene gloves from a non-bike (surf/canoe/wetsuit) company like those in the link above? How do they compare to bike specific gloves for warmth and handle bar grip?