I moved here from East Dulwich last year with my family, and so far, everything has been great. HOP has a better sense of community than ED. I think that's down to the fact there are more family homes and fewer rented flats. We've met a number of neighbours since being here and everyone has been very friendly and welcoming.
The transport options are better than ED. You've got the overground, rail straight to London Bridge and Victoria, and a different line at Crofton Park that will take you straight to Farringdon and Kings Cross.
And really don't worry too much about leaving ED. I still go there all the time. It's a 5 minute bike ride. Good luck with the move.