Pacov put it best

"Give Occulus an Interrupt and I will only play him. You can have Erebus. Hell, you can have two Erebuses"

I liked my view:

"No need to interrupt a flag lock when they don't have any flags to begin with"

He is certainly Tier II, and like Queen, does great when you've got Oak/UB/Ereb with you since all but Ereb have a quick interrupt you can use to stop most casts. He probably wouldn't work nearly as well if you've only got one other person on your team with an Interrupt. I wouldn't put him into the holy trinity quite yet since people just haven't learned how to deal with him (or play him ) but he does really have a lot of power it seems.

Tower Rook + Occ  in a lane is a tier 1 combo, in my opinion. Occ nukes creeps so the enemy never gets a chance to run in with the creeps, gives monk support, refills Rook's mana for more towerz. Plus, the AoE nukes of Chain Lightning, Blast Off, and Hammer Slam are just absurd. Basically have to run in on a sigil.

Sedna + Rook + Occulus, = OH GOD WHAT HAVE YOU DONE!

Super rook tank with recharged mana and health and regen aura and super aoe damage andsilence.

Tier Zero, see this replay:

http://www.gamereplays.org/demigod/replays.php?game=51&tab=upcoming&show=details&id=107136

"I was singing rocket man by Elton John because I call my Oculus Rocket Cow"

That is just awesome. Also, great song.

Thunderstruck by ACDC is also a good option.

Ole Doc Occ is the minion master.  Those lighting balls are outrageous, especially with a horn of battle.   Most I got them up too was 47 dps each.  

Occ is the king of Tier 2 DGs by an overpowering amount.

His HPs are rediculous. His chain lightning nullifies any skills that take advantage of surrounding units.

Unless you stun him, you cannot kill him. Sigil + Blast Off makes it nearly impossible to take him out mid game+ because of his ludicrous HPs and monks.

He would be overpowering if he had an interrupt, but he doesn't. These of course, aren't a problem if someone on his team has an interrupt.

I would say he is Tier 1 when teamed with any of THE 3(oak UB or LE) in a 3+ player game. 

Or Tier 1.5 when you are playing a Tier 2 only game, or 2on2. At which point he is your best DG after THE 3 & Rook.

Que Twilight Zone Theme.

*faacepalm*