Cons- it is more expensive. At some point I think though with the way boarding prices keep going up, that we will come out ahead. I could not have afforded to board 2 horses, but I could afford to keep 2 at home.
You are tied down if you can’t find someone to take care of the horse- to a degree. I believe horses are happier outside, and my horse has a run in and a pen made of panels. The panels were expensive, but she cannot break them and there is no other maintenance besides priming and painting small areas where the paint has gotten chipped. I feed lots of good hay, and she can get by overnight with a large, small hole haynet (those things can hold like a bale). Longer than that, a neighbor or friend will horse-sit for me. They don’t mind because I make it super easy- just stuff a haynet and check the water tank. They don’t have to clean because she stays outside 95% of the time and I just give the pen a good cleaning when I get home- it’s pretty big and she’s not one to intentionally stand in manure.
It’s actually been more of a hassle getting the dog taken care of when we go away.
Not having an indoor- this does suck in winter, but I can usually still ride some - it might just be a 20m circle one day, but if it doesn’t snow again right away I shovel the other 20m circle (my arena is about 20x40). With an “8” shape you can work on a lot of dressage. 
Not having lights for riding- though we did add a bright (little too bright, unfortunately) light outside, and I’m planning to experiment with an LED work light.
Your house will get dirtier (at least, mine did). I don’t make housekeeping a priority, and it seems like things get dusty faster than they did when I didn’t have a farmette. It’s not horrible, but I do think it’s a little dirtier.
It is more work. You have to feed and pick up manure, and my arena was hand built- I dug out some old posts, cleaned up the ground, shoveled and carted and dumped fines and sand, and I rake by hand. We put up the fending ourselves- again, I used panels, but dug holes and set the posts (to be fair, hubby dug the holes with the auger, I’m not big enough). But I like being outside and getting exercise, I hate gyms and won’t work out in one. I like that I’m accomplishing things with my effort.
Hubby sort of resents the time I spend mowing and tending the arena. He resented me spending hours at the barn when I boarded though, so that is no different. This way if he wants to grab me for something he just has to hollar out the back door.
Pros- the care for my horse- I feed her lots of nice hay and beet pulp that I don’t mind soaking, and supplements that I don’t mind measuring and adding. She’s got more room to live in. I can blanket/remove blanket easily.
I see her twice a day. She is always happy to see me. It’s a pretty great feeling. Even when I don’t want to get up, I’m happy to be out with her once I am. I often spend extra time out with her even when I don’t mean to. The sunrises are beautiful. The sunsets are beautiful. The moonlight is beautiful. I never took the time to appreciate the sky as much when I boarded. I like to just stare at the horse and the property and just walk around a little.
I do ride more. I went from riding generally 2-3x a week to 4-5x a week, and I do not think my riding would have advanced if I still boarded. Driving to the barn, getting the horse, taking her into the barn, sometimes having to deal with other people in the ring or the crossties- it was impossible to get a ride in if I only had an hour. At home, it might be only 30 min of riding, but 2 extra 30 min rides a week makes a difference- and usually it’s not that short.
I have my arena to myself, the footing is not too deep, and there is no barn owner’s junk stuck in a corner. I don’t have to pay for my trainer to give me lessons at my house. I am fine with riding alone, I feel like my horse and I are pretty much communicating with each other the whole ride so I don’t feel lonely.
No commute to the barn. Whenever you want to visit horsey, step outside.
Kiddo also doesn’t have to be bored at the barn while I ride- if his dad isn’t home, it doesn’t matter, he hangs out in the house and if he needs me he can just come outside.