Is Finchley in London a nice and safe place to live?

I am moving down to London from Leeds in the next six months (hopefully!) and am looking at flats to buy. I don't know London that well and am looking for a nice and safe area which isn't too far out of London. It needs to be reasonably affordable but my main concern is that I feel safe there as I have a dog and would need to walk him in the evenings. Any help would be great. I'm primarily looking at North London but would consider any part of London apart from East London as I don't know anybody who lives out that way. Thanks