I lived in a place about this size in Amsterdam for a year. I did not have a ton of 'stuff' at the time and for obvious reasons it's better if you can take a minimalist approach to physical possessions. I liked it OK; I had a bit of a view, it was quiet, I was single at the time so it was easy to keep tidy. Living in a similarly small space with my wife before we got married was stressful. We're both inclined to be cluttered but whereas it's easy to manage your own clutter it's trickier when you share. I live in a house now and it's full of stuff - it's like when you get a big hard disk and fall out of the habit of deleting things because you don't really need to manage the space any more XD

If I was single again and needed to be in a dense city I'd consider such a place - though not at these prices - I don't like dealing with roommates, so I'm willing to pay for solitude. But I'd give serious thought to whether I might be better off living in a more rural area and having more space to play with.