No one ever prioritizes taking this when it's up, and there's good reasons. In terms of numbers (stat wise), this drag gives the lowest amount of raw stats. It also takes way too long for the healing to kick in (the amount of time you have to avoid taking damage is way too long). Finally, it's the riskiest dragon to take, because it slows you while you fight it.
CancerBasedGod1 votesIt's not worse than cloud... It is the best for a significant portion of the cast that need sustain. 
Revali1 votesgalio and cho'gath have sustain.
CancerBasedGod1 votesCho isn't nearly enough for his late game. Especially now that he builds more HP, it is very unlikely you fill up on minion kills. Galio is also fairly limited unless I'm mistaken on that one.
Revali1 votes
something that's core to both of them. the sustain cho and them have for lategame isn't great sure, but during laning (where its best used for cho'gath) it's more than enough, since it also gives him mana. galio's can get almost half his health back later on if he can just tank a minion wave.
CancerBasedGod1 votesStill much better to have an ocean late on cho. Works with spirit too.
EndlessSorcerer1 votesOcean Dragon is probably the best dragon for tanks and supports.
Heck, Ocean Drake is better for carries than Infernal Drake is for tanks, supports and many fighters.
Salron1 votesOcean Dragon is probably the best dragon for tanks and supports.
No that's called the Cloud Dragon
CancerBasedGod1 votesNo it isn't... Many tanks need the sustain, especially as the game goes on... Cloud is never the best... 25 out of combat movement is just not that relevant.
ZephyrDrake1 votesNo that's called the Cloud Dragon
what would a tank or a support want with cloud drake? tanks shouldn't be needing the extra MS since they should already be with the team. What tanks want is a form of sustain or a way to deal damage to structures so mountain and ocean are the best drakes for tanks. A tank is the very first champion to take damage in fights usually so cloud is pointless on them and infernal is even more pointless since most tanks don't bother building damage items to begin with.
Supports would much rather have the extra mana sustain since if you are a roaming support chances are you already picked a champion that helps with roaming or you picked mobi boots which are superior to cloud drake more often than not. Sorry but Cloud Drake is only useful to splitpushers and teamcomps that want to move around like crazy, aka not siege comps and most team fighting comps
Cocho1 votesIts funny because when the drakes were introduced, Ocean was the best and it was immediately nerfed.
Mountain Drake has 50 more ad (150 AD) , more mr, more armor, and more health than ocean. Cloud has 50 less AD than ocean. Infernal has the same stats as ocean.
Whether or not it is the riskiest really depends on the situation.
Cloud2731 votesIts funny because when the drakes were introduced, Ocean was the best and it was immediately nerfed.
Mountain Drake has 50 more ad (150 AD) , more mr, more armor, and more health than ocean. Cloud has 50 less AD than ocean. Infernal has the same stats as ocean.
Whether or not it is the riskiest really depends on the situation.
Infernal offers way more than ocean does. You forget you have to avoid taking damage like 12 seconds in order to get any benefit from ocean drake. With infernal you ALWAYS have the extra damage. And yes it is the riskiest dragon in the game. It literally cc's you while you kill it.
Cocho1 votesInfernal Drake is a different argument, I agree it should be changed. I don't feel the same about ocean.