I have... but honestly.. I find it boring compared to larger scale battles. Dueling in the pits has the advantage of not losing any of your stuff.. but that in itself takes away from some of the excitement. If you have nothing to lose, then it doesnt hold much interest for me personally. Also, everyone that wants to duel you always wants to set restrictions on what is "allowed", stacking the odds in favor of themselves. I dont see the sense in that. It doesnt really prepare you for dealing with what you will run into outside the dueling pits. It helps, I guess... but its not as good as just training against your guildmates outside the pits where the only rules are.. there are no rules. That is of course, only my opinion.
Dueling would be much more interesting if they did away with the ability to set anything or restrict anything.. it would be ok if no one lost anything.. I can understand that a lot of people dont like losing their stuff.. but it should be .. whatever skills you use, whatever items you use, whatever ever spells you cast.. is entirely up to you. Bring your best stuff and give it your best shot. If you recall out, you lose the duel. Again.. just my opinion.