User blog comment:StrategicMagic/The Most OP Item in League of Legends is.../@comment-6499169-20130406220240

Well, for now, I'm only going to argue about it being better than doran's blade on ADC

First of all, you only have two examples of ADCs in your lane section. Ezreal mainly uses autoattacks and Q to trade (Q is maxed first out of all of his skills) and Q scales much harder off of AD than AP. As in, 5x better. As for Urgot, you would be able to spam a few less Qs with a doran's blade, but they would hit a bit harder. Also, running out of mana as an ADC isn't really a huge problem, even when you start blade. If you're going in to harass/trade that much, you are probably missing quite a few CS, making the ring less desirable. Most ADCs trade using autoattacks so the extra mana isn't that important.

Also, you might be able to spam skills more over time because of the mana regen, but in a straight up fight, the blade would be better. It would provide more damage for each autoattack, and most ADC's main skill scales off of AD. (Not to mention you would get a small amount of sustain in the fight from the passive) So in that short period of time, whether or not you started ring or blade, you would still get the same number of skill usages, but the one that started blade would hit harder, which is better for the fight.

Blade gives health sustain while ring gives mana sustain. For an ADC, health is far more important because farming is generally prioritized over trading. Not only will the 10 extra damage help last hit, but 5 HP EVERY hit will add up and allow you to remain in lane longer. A champion with 1 HP and a full mana bar can't really do anything. A champion with a full HP bar and 1 mana, can still do their job as an ADC in lane.

Also, you say that the ring will give over 500 mana from the last-hitting bonus over time, but 5 mana pots will heal the same amount and only cost 175 gold. (Not to mention that many lower elo players aren't very adept at last-hitting and will not get anywhere close to 100 minions/500 mana in 15 minutes)

Of course, the ring is still viable, like you said, but I don't think it's better than a blade.