Hoping to avoid igniting a Cuban/Puerto Rican flame war because this is such an old, played out controversy, but the hook of Oye Como Va is so similar to Cachao's Chanchullo (recorded many years earlier than TP's Oye Como Va) that many give credit to Cachao for writing Oye Como Va. As far as I know, Cachao never publicly claimed credit for writing Oye Como Va and TP never publicly gave credit to Cachao for writing it, although there is no doubt TP must have heard Chanchullo before he recorded Oye Como Va. Here is a somewhat Cuban-biased description of this very old, tired controversy.
http://en.wikipedia.org/wiki/Oye_Como_VaAlthough the link to reference 3 in Wikipedia doesn't work, the article quotes Puerto Rican salsa expert Max Salazar (RIP) as saying "Cachao's tumbaos for his 1937 composition of Resa Del Neleton (later changed to Chanchullo) inspired Tito Puente's signature tune 'Oye Como Va'."[3] I am willing to leave it at that, this is an opinion controversy that will likely never be definitively settled with objective evidence. Listen to them both and decide yourself. Please let's not get emotional over this.