It's next to my house and I have seen more than a few amazing photo opportunities, always with the camera at home or in the bag. There was almost a serious incident a while back when a Citation out of LCY kept climbing beyond it's cleared altitude heading North towards a descending THY B777 heading South and descending. Both were in cloud and TCAS procedures were not properly followed. For a time afterwards, all LCY traffic was forced to read back the 3000 ft limit when they got their clearance. That has now stopped.....
It might be safe but it's not what you'd call ideal IMHO. The fun bit of going into LHR over Canary Wharf is watching the BA ERJs powering out of LCY and heading (apparently) right at you.