It's Ilha Grande, so don't expect the Ritz. This place is clean, the breakfast is decent, the wifi is free and mostly works, the staff is generally kind, and the garden is pretty. The rooms are basic, the shower's water pressure is low, and the water gets only warm, not hot (but that's probably to be expected in this location). Pousada Cauca really deserves a 3.5 rating: better than average, but not "very good." Basically: a place to sleep and wake up when you're not tramping through the jungle.
Note: Not a lot of English speakers on the staff, so if you need/want help planning your Ilha Grande activities and aren't good in Portuguese you might opt for another pousada.