It really depends on the personality of the sims and specific story/vibe going on. I've realized I do a LOT of weddings (just got the achievement for "serial monogomist" on my current save, lol) and I always try to go with what seems right for the specific couple.
So, I downloaded a spooky graveyard lounge for Morticia and Gomez.
https://i.imgur.com/AX76EDH.png
These two actually two "weddings"--one big lavish public one with Miko friends contacts (she's in the politician career) and a private "wedding" with just the two of them where my "sim-self" Fanphoria Mercury could flaunt her alien-ness without freaking anyone out.
https://i.imgur.com/YXbG1Yc.png
https://i.imgur.com/FeuWmkQ.png
These two were impatient, and proposed and then immediately eloped at this tiny "chapel" that I'd placed in world.
https://i.imgur.com/mjOjPDK.png
https://i.imgur.com/TGV2WXq.png
These two had been together for ages already, and had a quaint but festive backyard wedding, with their three teenage kids helping out on cooking and hosting duties.
https://i.imgur.com/5WSpis6.png
These two had a small (family only) rather formal and "important" wedding at a proper cathedral with a graveyard, as they were uniting to major vampire dynasties.
https://i.imgur.com/IS8N3XD.png
This romantic sim threw a lavish wedding at the von haunt estate and married her vampire betrothed at the stroke of midnight.
https://i.imgur.com/NBtbHD8.png
This sim who loves the outdoors also had a lavish Von Haunt estate wedding...and then a smaller backyard elopement for her second marriage, after the first one didn't work out ;-P
https://i.imgur.com/awLAULB.png
https://i.imgur.com/gTYROqo.png
These two were still pretty poor when they got hitched, so they eloped in the ruins, and threw a cheaper party for all their friends after.
https://i.imgur.com/51qPf6o.png
https://i.imgur.com/r0eczCF.png
This trendy young romantic city couple got threw a big wedding at the Center Park.
https://i.imgur.com/PL1W6nt.png
This was a whirlwind relationship where the met, went on their first date, got engaged, and then eloped in the kitchen all in one day lol
https://i.imgur.com/S5OBs9y.png
These traditional types had a small family wedding in the chapel.
https://i.imgur.com/IXWW1xq.png
These frugal artsy types eloped outside the museum.
https://i.imgur.com/ArAaD0J.png
These two had kind of a controversial relationship, as the were basically brought up as siblings (each born from an abduction through a different parent) and eloped at the von haunt estate.
https://i.imgur.com/unBttmh.png
This successful and born rich artist married her outdoorsy beau in the newly renovated Municipal Muses courtyard, in a BIG and BOISTEROUS wedding
https://i.imgur.com/0boXAlF.png
These two wanted to show off their swanky new apartment (didn't really work out, but still, can't knock the view).
https://i.imgur.com/CC9pvu5.png
And these two took advantage of the romance festival timing perfectly with their wedding plans.
https://i.imgur.com/KfJCuu4.png
And I've had elopements at the bluffs or on dates, and several other home weddings as well, sometime multiple generations in the same home. It all just depends on the circumstances and what vibe I get from the couple. I've got my tried and true ones of course--the rebuild of the von haunt estate I use is great for weddings, in a practical and aesthetic sense--but I like to try out new things too. Another pair of my recently got engaged, and I'm think about a home wedding for them, since she has the mansion baron aspiration and they've just moved into a pretty nice place and I imagine she'd want to show it off. I'd want to make it extra EXTRA nice, so we'll see what I an manage lol ;-P