With any large company, your experience can really vary based on your department. They do have frequent layoffs. (Jun 2013, Jan 2015, Jun 2016 for larger ones and several smaller ones in between those dates).
MSS (a.k.a MeSS) is a disaster, stay away unless you like working in chaos with clueless management that refuses to do anything to change that. They can't deliver anything.
There is also a negative culture in that group that thinks you get more by putting people down. Cambridge- you need to like working with open desks, no cubes. One manager, Mike B, thrives on berating developers. (he is a bully)
Yes, they are moving to the "unlimited days off" where your manager has to approve any time off, and Mike actually said that if you are sick you need a doctors note and need to tell your entire scrum team exactly why you were out. How is that even legal?
Your health is none of anyone else's business. Two years ago several people complained to HR about him and surprise, surprise, they were let go in the Jan 2015 layoff.