Not all I/O boats are the same. What do/did you have before? In my own experience, I found our jet and the others I've been on to be considerably louder than any other boat I've been on, and with a tone that was frankly not pleasing to the ears. Some of that comes down to simply running at much higher rpms than a comparable V6 or V8 powered boat, it also comes from exhaust that exits above the water level on plane and from the noise created in the hull by the pumps themselves as they process a huge volume of water. For those riding in the bow, it probably isn't all that different as most noise up there is wind and water with the engine sound being blocked by the windshields. Behind the windshield, though, is a different story. Honestly, if relaxed/semi-quiet cruising is a priority, I'd definitely expand your search.
The difference between our Yamaha SX210 and the MB v-drive we currently have, is very very noticeable. Our guests didn't complain on the jet, but nobody did much talking while underway because it was just too loud. Several have commented on how much quieter our current boat is, though, and people are always talking now while underway, not just when we're anchored in a cove somewhere. Just one man's experience.
