I took my mother to Peru in February to see the Amazon. It was a trip of a lifetime for her. We booked through International Expeditions and they did a stellar job of making all arrangements, meeting all connections and seeing that we had our needs met. I highly recommend them.
My mother is a rather overweight, out-of-shape senior, and some of the hiking was challenging for her-- although the pace was slow enough, the trails can be uneven, slippery and muddy, especially the canopy trail at Napo Lodge. Keep this in mind, although quite a large portion of the trip was also spent in open motor boats, which was just fine for her. We saw tons of wildlife and birds.
The accomodations ranged from glorified tent platforms at the Napo Lodge to modern air-conditioned resort style at Ceiba Tops. I preferred Napo because of the feeling of being right in the jungle and the tranquility of bird calls in the morning, but not everyone can deal with pit toilets and cold showers. Food was the same at both-- a bit bland, but plentiful and good variety. I just wish they had included more Peruvian local dishes. It was pretty much rice and beans and protein, with cabbage salads and flan for dessert.
One thing I wish I had known was to bring at least $200 in cash. There is no ATM in the jungle, and we wanted to tip our guides and hotel staff. Also, there are quite a few opportunities for buying local crafts. Bring plenty of ones and fives, and make sure they are in perfect condition. Local banks refuse to take creased, torn or dirty money, so the people can't use them. They will refuse your money if it isn't in good shape.
I also had the great good fortune to get Juan as a guide. He is a perfect host, and had to deal with some rather unpleasant people on our trip, which he did with good humor and grace.
Have fun!