PROS: No matter what you do, you're never going to be perfect enough for their child, so once you realize that, then you can act however the hell you want! Stop buying them gifts and thank you cards, you unsuitable a-hole, cause it ain't gonna matter!
CONS: Expect group texts to the both of you anytime something remotely dangerous happens in the city you live in, asking if that was near you and urging you to be careful (because you usually just go around being intentionally not-careful). Also they may try to fix up your significant other with a friend's kid while you're still dating.
PROS: They're constantly starting arguments (usually over really trivial stuff like where someone left the 'good scissors'), but it makes for lively dinner conversation, and you can always just sit back, not offer your opinion, then bond with your significant other over how crazy they are. Plus you'll never feel selfconscious about swearing in front of them.
CONS: The everpresent gut-wrenching fear that this is how your own relationship will eventually turn out.
PROS: They've been divorced for a while and they're seeing other people, and it's fine; they seem really happy, they're really open and honest about it, they're generally very progressive, and they really love their kid so they're always happy to spend time with you.
CONS: Now you have to make up smalltalk BS with four people, not just two. And start over with a new person every time they start dating someone new, who is always just some nondescript fine adult person.
PROS: The massive extended family ensures that you'll get a trillion extra gifts for every relationship milestone, and family occasions are usually insane blowouts with tons of great food.
CONS: You'll be quizzing yourself on peoples' names before every family gathering, then you'll panic and not have the confidence to say anyone's name anyway and just smile through every conversation. Also every time your date tells you a story about one of the family members you'll never know who it was.
PROS: The mom just got high in the bathroom during dinner and is talking openly about it and laughing while the dad (who might be in his early 40s or mid-70s?) made a joke about bringing his gun in his suit pants and you're just now realizing it wasn't a joke. Buttttt WOW are you suddenly thankful for your own family! Plus they picked up the tab.
CONS: You'll constantly feel bad for 'judging' them, and remind yourself that every family has its own crazy quirks and there's no such thing as a "normal family." Then you'll see that their living room is decorated with ultrasexual paintings of Biblical scenes. Just go along for the ride.