>>28276608All the Deoxys forms have at least one crippling weakness. Attack and Normal forms can't take more than one or two hit even resisted ones. Defense form is Taunt bait and doesn't have any offensive presence. Speed form is the most powerful and dangerous in my opinion since it's so versatile, but none of its attacks or defenses are above 100, so if you have something that can handle a strong psychic type like you prepared for Latios, you should be able to handle Deoxys-Speed.
Uxie is just a bad Deoxys-Defense. It has a worse movepool and isn't particularly threatening. Mespirit is just a really bad Mew. Terrible movepool, doesn't really specialize in anything. Azelf is the strongest of those 3, but, again, if you prepared for any strong psychics at all you should be able to handle it. Azelf falls apart after one or to neutral hits anyway, it's defenses are really bad.
In the event coming up, the distributed Victinis won't know V-Create, so most Victini you'll be seeing in the near future will be nerfed (doesn't learn its own signature move by level up, how lame is that?) Victini has good allaround stats, but at the end of the day it's just a straightforward attacker and isn't particularly overwhelming since its best moves have drawbacks (V-Create).
Meloetta is an unfocused mess. You either try to get it in Pirouette form, which wastes a turn and does the same thing as Mega-Lopunny but with less move slots and it reverts back if you switch it, or you keep it in Aria form where it has similar stats to Latias but slower doesn't get Roost or Draco Meteor.
Zygarde is surprisingly easy to deal with. It's attack stats are very low considering it's a legend, it's a defensive pokemon with no recovery or healing. As a Dragon dance user Mega Altaria and Charizard-X outclass it in almost every way Burning Zygarde pretty much cripples it forever. It's like Hydreigon: Amazing on paper but not that great in practice.
