We did the 3 night, 4 day experience of Munnar + Houseboat in Allepey. Our driver, Vipin, was great! Very reliable, always early to meet us with a warm smile. Five stars for him!
The rest of the tour I would give 3 or 4 stars.
It's worth noting that there is little explanation of the history or the context of the places you're going to, so bear that in mind if that's something you're interested in.
It's also worth bearing in mind that it's not all inclusive. We were aware that entry to parks, museums, sites weren't covered but we were also upsold some other services like the Jeep experience in Munnar, and a boat tour in Alleppey. These were definitely more expensive, but we didn't feel too forced to take part.
The Rivulet hotel in Munnar was quite nice but a bit dated and the houseboat experience in Allepey was also nice overall but the houseboat we stayed on was not very clean and a different company from the one in the itinerary. I'd recommend doing a bit of research on accommodation yourself and being specific with what you want when you book.