Pros
Square has a great mission and it makes the bad days easier to deal with. For a tech company, the privilege of coming to work every day and not feeling like you're morally failing shouldn't be understated. Square recognizes that it has problems and is mobilizing to fix them. They don't always get those fixes right but I'd rather work for a company that sees that its market share is slipping and does something about it rather than one that just lives in ignorance. There are some truly intelligent, very talented people at Square. If you land with a good manager, you'll be fine.
Cons
Tons of change. Lots of restructures. Senior leadership (innercore) doesn't always inspire a ton of confidence (a lot of them are pretty junior for the size of title they have). A lot of middle managers have been at the company for a long time and are complacent, unmotivated, etc. Company definitely suffered from Jack's time being split between Twitter and Block and is now scrambling to make up for it now that he's back to steering the ship. It also has to be said that there are also a lot of whiners at this company. A lot of people who have been here for a long time, made literally millions off of stock, and gripe about every little thing because it isn't the "good old days" of $200 share prices and lunch served every day at the Market St HQ. They whine about change but also whine about the current state of the company. Well, you can't have it both ways. Growth isn't the easiest because people stay. Most leaders are men, which is typical of tech but pretty glaringly obvious here.