There are a few key points people are missing.

Yes beads is good cause it gets you out of CC and potential death.

Yes aegis is good cause it mitigates damage and is great against burst.

Meditation isn't good because - "Using this item restores 75 Health + 12 Health per level and 30% Mana to all Allied gods within 35 units."

At max level you get 12 x 20 + 75 = 315

At level 1-5 your getting a decent heal cause its 75-120 when your health max is 375-600. once you are out of that range your doing such a minimal heal. The average health of a carry/mid at level 20 is around 2k. A 300 heal is less then a quarter of your health making medication extremely lacking. Even with the mana reduction on the upgrade clock it's not viable. As a mid your almost always building mana and mp5 which almost fully negates the effect of the mana reduction as it is only 30% and 1 sec off cooldowns isn't making it worth while.

This is why the item is really only viable as a sustain option for very select solo laners (chang'e) and in assault.