If you are not okay with change or managing change, you probably won't like trivago. Change seems to be the only constant at trivago, so the right frame of mind and attitude around change are an essential prerequisite for this job. However, this means a lot of exciting opportunities for those who seek them.
Another complant would be that salaries could be better. trivago seems to pay fairly for the market, but a bit more transparency would be nice. However, you do get a lot more with this job than just salary, including great flexibility and benefits that you're encouraged to use.
Finally, the lack of head count can make it difficult at times to manage workloads and meet all expectations. While they are careful with hiring, I don't quite think they're at the level they should be in terms of employees.