Xatu

Type Tier
Psychic / Flying UU
Statistics
Stat
HP
65
333
Atk
75
248
Def
70
238
SpA
95
288
SpD
70
238
Spe
95
288
Name Item

Mixed Attacker

Leftovers
Moveset
~ Psychic
~ Drill Peck
~ Confuse Ray / Night Shade
~ Giga Drain / Faint Attack / Haze

The only other Psychic / Flying-type. Obviously Lugia's better, but it's uber. Anyways, your first two moves run off STAB, and 248 Attack Drill Peck isn't horrible, but don't think you'll sweep a lot with it alone. Last two moves are toss-ups. Confuse Ray if you feel lucky, Night Shade so you hit everything non-Normal for damage, Giga Drain if you hate Golem and such, Faint Attack for Psychics not named Alakazam and Starmie, and Haze if you're suicidal.

Other Options

Toxic with Nightmare might be good for a laugh against Rest teams. Safeguard can help you and your team. As always, Thief is a good option since it can hurt certain Pokémon by taking their valuable Leftovers.

Opinion

Xatu is pretty fun to use. It's just outclassed by other Psychic Pokémon, and being part Flying only gives it more weaknesses that it can't compensate for. Xatu is strictly an underused Psychic, since Alakazam and Starmie can do much, MUCH more for themselves and their team than Xatu.

Counters

Most strong physical attackers, excluding those extremely weak to Drill Peck or Psychic like Heracross, will take care of Xatu reasonably well. Steel-types in general, including Scizor and Magneton, tend to be enormous pains because of their resistance to all of Xatu's attacks.