I had a 590nm Infrared Canon G11 with 1/1.7" sensor... the sensor was way too small with way too much noise even at 80 ISO. I'm sure it was the infrared contributing to the noise, etc. I never too many regular photographs with the G11 before the conversion, so I can't really comment on that.
The sensor in this Nikon P900 is even smaller than some of the other point and shoots. I'm much happier with the Nikon Coolpix A that I just got converted to infrared. Of course it doesn't have a 3000mm zoom and only a wider angle prime, but hey that DSLR DX sized sensor is nice to have in a point and shoot.