Threeways purchased a Musii a little while back now and have had some great sessions with it. It has 3 inflatable prongs with built in distance sensors and LED lighting and makes musical sounds as you press them in. The software runs on a little built in Linux machine and it is all self contained with an amp and speaker inside meaning it also vibrates. I always find that sound needs to be local like this for a meaningful experience, rather than coming out of a speaker over there on a wall which can be a little abstract. Since we have had the unit it has been updated to make the sounds less discordant which has helped, but the only other issue we have had is access. Wheelchairs can not get very close to it, but the company are very open to critique and they are apparently looking at something more lap based. Personally, I'd love these to be coming directly out of the floor or the wall!