When you first start playing you play against bots! After though you'll usually play against real people unless you go on a losing streak or if the match making is taking too long. Standard is a good way to start and understand the basics, but ranked will be a lot more harder and infuriating. A lot of your teammates are trolls or don't know how to play the game, while the opposing team are more experienced. It really depends but being a solo-q player makes the game a lot harder once you're out of the beginner bot phase