I love battling the Mix Tournaments in Double format and Unova leaders in Triple format. Those are the 2 tournaments I love best because there's no limit to who you use. I did had a tough time defeating my Celebi but I pulled in a good win. The only 2 Pokemon I lost to were my Dragonite and Feraligatr. Trust me, if you don't pick a good team to cover your defense, your Pokemon might turn the tables on you if picked by your opponent.