I use a cork when the fish are less active in the winter and more often cast and retrieve or jig in the summer when they are more aggressive and chasing baits.
I find most people who don't like corks are still using the old fashioned "popping" corks like this:
http://www.academy.com/shop/pdp/h-h-...ge&N=310008596
but if you use the clip on egg corks like these:
http://www.academy.com/shop/pdp/coma...23?N=310008596
then you wont have any more tangled lines, even with double rigs if they get wrapped up, a pop or two and it comes undone and straightens out.
I use the unweighted for double rigs and the weighted one for single rigs.
the clicker corks with the wires and beads and such are just too much for your line to get tangled in so I don't use em. when you try the clip on style egg corks, you will find all your frustrations with using corks will go away.
like anything corks are just another form of presentation and they can save a trip when fish are biting very slow and you need to keep the bait in the strike zone fish are reacting to or if they aren't biting and having that bait sitting in their face not moving away gets a reaction bite (or a frustration bite) from them so you don't go home empty handed.