I live in a pretty nice neighbourhood of Amsterdam. 15 years ago, when I moved here, my uncle (who is a cop) warned me not to live here because of all the crime (though the neighbourhood where he lives has a worse reputation). The population at the time was a decent mix. Lots of ethnic minorities, but also students and probably middle class families along the edges.
During the past 15 years, loads of new restaurants have opened here, there's a small movie theatre, the dodgy-looking call shops and phone shops have disappeared, the snack bar that changed ownership every year has now turned into a fancy wine bar. Some old buildings have been turn down and replaced, others have been renovated. Generally, this seems to me like a great example of gentrification.
And I'm sure housing prices are rising, and I don't doubt the new and renovated buildings are more expensive than the older ones. But the population doesn't seem to have changed all that much. Maybe there are more affluent white people now, but I still see kids from a variety of ethnic backgrounds play in the streets (though I don't see groups of adolescents and young adults hang around the square where that dodgy snack bar used to be), and there are still plenty of Turkish shops (though some have closed, sometimes to be replaced by a new Turkish shop, sometimes not).
I don't know how many people have been forced out due to the gentrification. They include my brother-in-law, who had lived there for ages until his house was to be renovated. But for the most part, the population doesn't seem to have changed much, and the neighbourhood seems to be more vibrant, more stuff to do, less need to go to the center of the city if you want to go out.
So if this is gentrification, my impression of it is pretty positive, though I don't have any stats to back it up. Of course with those people who hung around on that square, I have no idea who they are or where they are now. It feels safer, but that might be subconscious racism talking.