Pros
Free muesli, milk, coffee, soda. One can order personal parcels to the office. Conference allowances (although burdened with bureaucracy so I never used them). Possibilities to learn something. If you are a sociable type you will likely find your way around the organization, otherwise - no luck. Relocation support is substantial and I did appreciate that. The company has been profitable, so there are no repercussions caused by money shortage. 3 months notice period - will get in the way if you decide to change the job, and hedge you against surprises if Zalando fires you. Technology-wise, you can get some marketable keywords into your CV, so this could be a good option as a first job.
Cons
The place is not for introverts. A fun fact: HR department is called "Employee Experience". They will harass you with people leads, happiness surveys, feedback talks, development talks, but despite all that you would be the only person who cares about and can solve your problems. Creepy manager peeking over your shoulder to find another thing to report on you today so he would have an excuse to fire you is not an "employee experience" you want (I certainly do not). As in any big company YMMV depending on team. So if you are being interviewed for a position then ask to have a lunch with the team and see whether you feel comfortable or not. There are departments with consistently high attrition so proceed with caution. If you have an impression that Zalando will give you sort of startupey feeling - it won't. After last year's CEO changes, more layers in management hierarchy, and primary focus on protecting what Zalando already has - it is different place now. In my impression this is a common sentiment inside the company. These changes are not necessarily a bad thing, just do not go there with wrong expectations.