Real life>online
Online Pro: you can see if there is a physical attraction without the fear and embarrassment of rejection irl.
Online Pro: you ca chat a bit to see if there is a connection between you two.
Online Con: the pictures you are seeing could be fake
Online Con: Anyone can act like they are one way but are completely opposite irl.
Real Life Pro: Both can get a feel for if you guys connect and are truly compatible.
Real Life Pro: The person in front of you is the person in front of you and not a fake pic.
Real Life Con: The person in front of you could pontentially be looking to murder you when the date is over?

_@: (rare but can and does happen)
Real Life Con: That awkwardness if the date isn't going well.