Best place to do an Amazon tour from

My best experience in the Amazon was going from Leticia in Colombia to Iquitos in Peru by boat. There are loads of places to stop off where you get deep into the jungle. In Leticia you can cross into Brasil without border checks. The town just merges into both countries. And Iquitos is a remote city in north eastern Peru right on the Amazon river. I spent 5 weeks doing this and i done it independently. I stayed with locals and got to see lots of wildlife that they told me you wouldn't see in the tour routes. But i imagine it's possible to do something similar with a tour group and in less time. I went with a tour group in Ecuador from a place called Coca and also the jungle tour in Rurrenabaque in Bolivia. While both tours were good i didn't really see much wildlife. Mainly birds was all we seen. I also done one from Tena by myself and just hooked up with locals. Both times i done it with locals i got to see a shítload of snakes, spiders, monekys, etc.