Generally, people hear tarot more then any other deck of cards or in any other form of divination. Mostly because that is one of the common ways. But they aren't the only decks in the "fortune telling" world. Oracle cards are becoming increasingly popular, but neither are "better" then the other.
The main difference between the two though, is the structure and purpose.
Tarot has a more complex structure in that you have the major and minor, where as oracle, as few as 10 cards have been seen used.
Usually, oracle cards follow a theme to come across what they do.
A few current sets I have are The wisdom of Avalon set, which to me focuses more on insight and wisdom. And the Shaman's oracle set, which is meant to lead on a journey of self-discovery.There are many versions of tarot as well, but they aren't as set in theme some say.
Oracle is more so focused on life lessons, rather then details of a situation and are more straight forward, requiring "less" of an interpretation. Their easier depiction draws in more younger, new readers it seems to me personally. The images make it easier to see what is being said.
Generally, Oracle cards are often using a one card, a three card, or a five card spread as well, all based on the type of answers and insight wanted. There are many other unique spreads used though, in which you can search google to see.
You can find oracle cards generally where tarot is sold, in the same area. Or there is the online approach.