They're very similar to redcurrants (they are the same species and can interbreed to produce "pinkcurrants", which look very weird). Some people say whitecurrants are a bit more delicate than red, especially less acidic, but I think the variation between cultivars and growing conditions more than makes up for that (in theory the best variety of white growing in the best possible conditions would be the sweetest, mildest currant going, but I like my currants more acidic anyway!). You can use whitecurrants on their own to make jelly, which can be very pretty and pale, or with white grapes. Redcurrants are often used with strawberries to bulk them out and help jams set (and add a bit of a bite if the strawberries are bland), and there's no reason you can't use white.