I visited this site in February 2015 on a day trip from Cairo together with a few hours in Alexandria. We first visit the NEW church which is NOT the UNESCO part. This takes an hour to see, it's nice, don't miss it. From there we went to the archeological site which is DIFFICULT to find. Google maps is your friend, it's actually only about 10 minute drive over some dirt roads but they kind of are criss cross but finally we made it. There seemed to be nobody there but we could freely walk it and then someone turned up from the small wooden church there. He asked if we wanted him to show us around, we declined (as we had a Egyptian friend with us who told us to - you know, to pay after which was not agreed). We walked there just over an hour. The underground things are mainly filled with sand/water. There is some restored parts and you can clearly see all the foundations.
On my blog you find some pictures. Its worth the visit especially if you like UNESCO sites. i would not recommend the regular traveler to go there.