Giratina-O is one of the most prominent Pokemon in Ubers. He It(1) has access to a wide arsenal of moves, like including Draco Meteor, Dragon Tail, Earthquake, and Shadow Sneak, which and more, while these(2) are backed up with base 120 offenses. It is definitely one of the most ntable forces in Ubers, and is capable of checking It also notably checks(3) common threats such as Mewtwo, Groudon, and Arceus. With it's ability it can freely switch in and out because it does not take (Toxic) Spikes damage. Thanks to its ability, Levitate, Giratina-O is immune to Spikes and Toxic Spikes.(4) It’s probably Mostly known for being as one of the best spinblockers in the game, it can also run an effective mixed attacker set that puts pressure on stall teams with constant shuffling and hard hits. and it’s Mixed Attacker set, that allows it to put a lot of pressure on Stall teams by constantly shuffling and hard hitting. However it does not stop their: The fun doesn't stop there—Giratina-O can effectively run a SubCM set to turn common Pokemon like Forretress to a set up that turns common walls such as Forretress into setup bait. But since As Giratina-O does not have a reliable recovery move, it can trade Substitute and a coverage move for Rest and Sleep Talk, and by that healing himself instantly to keep itself healthy. Giratina-O does have his its flaws, however. No way of healing itself besides ResTalk is really suckish. This makes him also weak to status, especially poison, coming from unpredictable Pokemon such as Forretress. A lack of reliable recovery is a turnoff, as it makes Giratina-O prone to residual damage, especially poison. It also isn't particularly fast; base 90 Speed only allows it to tie with common threats, such as Kyogre and Dialga, if running max Speed. Weaknesses to common Dragon- and Ice-type moves isn't doing any favors, neither. Regardless, Giratina-O is not to should never be overlooked when making your team.
If there's anything you don't understand in that check, feel free to ask. Also, if you think I missed something, you can bring that up as well. Remember, everything gets GPed twice for a reason ^.^
Sandz didn't tell me what the next paragraph will be, so you'll have to wait for him to post it up :P