Tech is good but customer service is horrendous.
Like many others here I've had bad experiences with N26's customer service. The first time while verifying my ID the woman just hung up on me when I kindly asked her to repeat what she had just said, so I had to start a new session and do everything over again. There was no way for me to know her name or report her after, so the customer service representatives aren't held accountable for their actions.
The second time, I had a Metal card which comes with "Premium" customer service, but when I needed to change my phone number, I started a support session on my phone, but had to wait about 30 minutes. During that time my screen turned off and I lost the session, so I started over again but on my computer this time. I waited for an hour, and I was 3rd in place, but it was too late in the day so they just shut down their customer service completely and I had to try again the following day. 
Also note for those who use Spaces and Overdraft. You will be charged for Overdraft even if you have more than enough money to cover the overdraft in your Spaces. I had more than 1k€ in spaces but got charged for my main balance going negative. That's a scam if I ever saw one. 
Overall the app and tech is great, but N26 still falls short in a few too many places.