I didn't go back, it's now 22 months since I last worked. Ds3 is 21 months.
Pros-
I'm at home (obviously)
I get to collect my 5yo every day, spend so much time with dc3 and am around for teenage dc1 who is about to go to high school/GCSEs etc.
I have., in theory, a really relaxed, easy going lifestyle. We do fun stuff. We have time.
Dh can work as many hours as he needs to. It is prime time for his career, in his industry. He currently works his socks off.
School holidays, childcare, no worries.
Cons
I miss grown up, professional people.
I may be off, but all my friends went back to work. I actively seek to make friendships with people I vaguely know (ie through Facebook, school, organising coffee mornings for charity) or go to lots of clubs and groups alone.
I spend a lot of time at home alone with a toddler and in the early days there isn't time to read/hobbies/ do anything except childcare and housework. This is slowly starting to change but I have to make myself pick up a book once he is playing and just read a page, because the temptation is to clean/ tidy.
It is a bit like Groundhog Day.
The domestic admin is never ever finished. I never get to 'clear my desk', I get no bonus or recognition. So you survived the day huh? Try again tomorrow!!
This is not very mumsnetty but I do 99% of domestic work, carry virtually the whole 'mental load' for the household, and have very little free time or personal spending money. This is very draining after two years, and I can imagine when I return to work I will be very tired of it.
And the biggest con- I know, 100% that in order to return to my profession I will have to retrain/volunteer before I do. I have decided to take this break, for my family, but I know for a fact that it will have a definite negative effect on my working future, possibly For ever but definitely the immediate few years after I return. I don't know if I regret this, but I definitely acknowledge it. Additionally, having 3 children, 2 of them primary age when I return to work will also hinder my chances- I will likely never return full time until the youngest are both teenagers.