Ranked pros: good when you just wanna get several matches in a few minutes without too much effort searching and waiting, training while waiting after every match allows me to practice what I messed up in the previous match, psr is fun, get to compare win % among all my characters, get to play more people (in theory), player rooms are kind of exclusive if you are looking to fight new people
Cons: ranked has worse players (in my experience), worse players often means more salt, I always end up playing the same person over n over (fix this!), gets old much faster after long waits between every match, a lot of people just dodge
Since I stopped caring about arbitrary numbers I stick to player matches.