We took the Egypt cruise in November and it was the trip of a lifetime. The weather was great, usually in the mid 80's , cooler at night. When we got farther south around Aswan, it was warmer, but still not unbearable.
One of things I liked best was when we spent time just cruising along the Nile, watching the scenery and the people along the banks, working their farms, fishing, swimming, etc. Often they would wave and yell "Hello."
I recommend the trip to Abu Simbel. It means a very early morning departure, but it's worth it. We got to see the sun rise over the Sahara.
Cairo is not a very pretty city, but the Marriot is lovely.
Just a warning, be prepared for aggresive street vendors everywhere you go, and carry your own toilet paper.