It has been many years since I visited Egypt, and unfortunately I only stayed a few days, so my experience is limited to Cairo.

I certainly intend to return because the country has so much to explore, and I would like to spend a few weeks going to Alexandria, Luxor, and Hurghada on the Red Sea for some diving.  

I am also looking forward to seeing the new, world class, museum in Cairo.  The old museum just didn't give due respect that the richness of their history deserves. 

You may find Cairo to be a bit polluted, and the streets a bit dirty.  But, it is a huge city after all. 

There is a strong culture surrounding tourism, so expect the hustlers to be out as aggressive here as I have seen anywhere.  

But, any downsides to visiting Cairo are well out done by the awe inspiring history. For example; Before I went, I knew the Pyramids were large, but nothing prepares you for standing next to them and seeing exactly how immense they are.