Deoxys in Pokemon Go

Deoxys has been the EX raid boss for some time in Pokemon Go, and now, as part of the Ultra unlock, it has come and gone in regular raids. It has four forms; normal, defense, attack, and speed. It is not the best Pokemon, and certainly does not live up to the legacy set by its predecessor in EX raids, but some of it's forms have certain niche uses.
Deoxys, being a psychic type Pokemon, is weak to Bug, Dark, and Ghost type attackers. The best counters to use will slightly vary by form, move set, and weather, but generally you will want to front load with glass cannons such as legacy Gengar and Weavile, and follow these with bulkier counters such as Giratina-Origin, Tyranitar, and Shadow Ball Mewtwo.
Normal:
Normal Form Deoxys has a max CP of 3160. It has a massive attack stat of 345, a defense stat of 115, and a stamina, or health stat, of 137. 345 is the second highest attack stat in the game; higher than Mewtwo's, and second only to Attack Form Deoxys. This seems like it would make Normal Form Deoxys a monstrous glass cannon; although this is true, it is too frail to be consistent. Even Gengar, perhaps the most iconic glass cannon, has a defense stat of 149 and a stamina stat of 155.
Additionally, Normal Form Deoxys has a relatively poor move set; it has access to the moves Zen Headbutt and Charge Beam, and the charge moves Hyper Beam, Psycho Boost, and Thunderbolt. The only usable charge move it has is Thunderbolt, as on a Pokemon as frail as Normal Deoxys, Hyper Beam and Psycho Boost are too slow to be considered.
However, Normal Form Deoxys does have one niche use; it is the highest DPS electric type attacker in Pokemon Go. The only problem is it is incredibly frail, and there are options such as Electivire that do the same job with far more bulk and without costing rare candies. It's probably best to leave Normal Form Deoxys collecting dust.
On the raid side of things, Normal Form Deoxys can be beat by 2 trainers at ultra friends using level 30-35 counters with relative ease.
Defense:
Defense Form Deoxys has a max CP of 2274. A relatively low attack stat of 144 keeps it from performing in PvE, but a massive defense stat of 330 and a stamina stat of 137 allow it to perform extremely well in PvP.
Defense Form Deoxys has access to Counter and Zen Headbutt for fast moves, and Psycho Boost, Rock Slide, and Thunderbolt for charge moves. Counter will be your fast move of choice, as it is a phenomenal PvP move, dealing 4 Damage Per Turn, or DPT, and earning 3.5 Energy Per Turn, or EPT. On the opposite end of the spectrum, Zen Headbutt is a terrible PvP move, dealing just 2.7 DPT and earning a abysmal 2 EPT.
For charge moves, you will want Psycho Boost, and can chose between Thunderbolt and Rock Slide for extra coverage if adding a second move.]
Defense Deoxys can be beat by 4-5 players using level 30-35 counters at ultra friends with some difficulty, or 3 players using level 40 counters at best friends.
Attack:
Attack Form Deoxys has a max CP of 2580. It has an insane attack stat of 414, the highest in the game, but a defense stat of 46, one of the lowest in the game; 677th out of 681, to be exact. A low stamina stat of 137 doesn't help it's bulk much. It has the highest DPS in the game, but absolutely abysmal TDO prevents it from being usable in all but some very select, niche situations.
It has access to the fast moves Poison Jab and Zen Headbutt. STAB makes Zen Headbutt the fast move of choice.
It has access to the charge moves Zap Cannon, Psycho Boost, and Dark Pulse. Zap Cannon is a one-bar move that may never be used, and Psycho Boost has a long cool down during which Attack Deoxys could faint. Dark Pulse is the charge move of choice.
Speed:
Speed Form Deoxys has a max CP of 2879. It has a attack stat of 230, and a defense stat of 219. It has a Stamina stat of 137.
It has access to the fast moves Zen Headbutt and Charge Beam.
It has access to the charge moves Psycho Boost, Swift, and Thunderbolt.
Speed Deoxys is terrible in Pokemon Go. It has very balanced stats, already putting it behind as Go favors extremes, and it's main selling feature doesn't exist in Pokemon Go: speed. There is no speed stat in Pokemon Go, leaving Speed Deoxys very mediocre.