Pros
As with many big startups in Berlin, HelloFresh is a very international and diverse organization (with the exception of the senior leadership team.) Office is well located and surrounded by other interesting startups. If you don't need much structure, and don't really care about things like "mission", "values" and "purpose", you can learn a lot of practical stuff on the job and have opportunities to go up somewhat within the company. You will also likely be involved in interviewing potential hires and be able to learn from that. There are still a lot of competent people working there, although the turnover as of late has been immense.
Cons
HelloFresh, especially post-IPO, became completely obsessed with revenue at the expense of everything else. Senior leadership, with a mix of inexperience and arrogance, created a culture that has been pushing away a large number of long-standing employees, who started feeling their voice was irrelevant, and that their work wasn't really making a difference. I have personally left the company feeling that standing up for what you believe is best for the company, if it goes against the leadership's ideas, is a horrible idea. There is also an obsession with hiring, even if there are numerous cases of people with very little to do due to the lack of structured product management. And only increasing head count comes second to revenue. One of the consequences is an office that has for a long time been overcrowded and where working in the afternoon becomes impossible due to the lack of oxygen. In the summer, it literally becomes a sweat shop. A lot of people have said HR is ineffective, but the reality is that senior leadership's "command and control" mentality does not allow for much. Feedback, in its true form, is a foreign concept, despite claims of an "open" culture and performance review processes that are nothing but a lot of work because they still don't train people on how to do it properly. When those in charge are in fact not fans of feedback and do not take it for themselves, it is no wonder the culture gets screwed up at scale. Overall, the biggest issue of HelloFresh is hiring a lot of talent only for the ones at the top to have influence and decision making power. This strategy (or the lack of it) has certainly got the company to IPO (thanks to an impeccable job in marketing and operations) and become a billion dollar company but is now showing its long term effects: talent flocking away at a very fast clip, and the stock price going down hill at the same pace.