A friend and I stayed at Sacha Lodge a few years ago and had a wonderful time. It wasn't busy and we had personal guides daily - one English speaking and one native who was very knowledgeable. The room was wild enough to be interesting and comfortable too with a private bath. The rooms are like cabins on stilts and not too close together. We walked through the jungle paths each day as the guides educated us on the flora and fauna. They provided tall rubber boots so we didn't get bitten. The food was fine and the location lovely.
If you want a more sedentary jungle experience go to La Selva Lodge which has fancier food, more people and you mostly travel in dugout canoes through the jungle.
Both were lots of fun.