Originally Posted by Whi
If you can spam, you build tear not ROA.
Tear is probably a bit weaker on most champs than a catalyst start. Though there are about four to five that do well with a tear if building into a manamune, or if you are Ryze and maybe Karthus. Then on the flip side, Rylai's is better on some champs.
RoA delivers health, mana and ability power
Rylai's delivers health, ability power and slow.
AA/Manamune, Mana + damage.
If your champ already has a slow, you might not want to stack it.