We have Furuno Navnet II at the nav station and at the helm, networked with C-Map charts, Laptop at the navstation with MaxSea TZ and Navionocs and C-Map charts and OpenCPN with Google Earth satellite charts plus WiFi connection to a tablet at the helm to mirror the laptop. We also have a B&G plotter where the Forward sonar used to be, with Forward Scan and Navionics charts. Our experience in the S Pacific is that the C-Map charts are generally good, Navionics less so, especially in Fiji where Navionics sometimes doesn't show passages where they exist and shows reefs where there aren't any and doesn't show them where they are.
In the S Pacific ALL electronic charts suffer from the fact that a lot of them are based on very old paper charts made before WGS 84 datum and while thay can be accurate to look at , things are not quite in the right place. In New Caledonia and FP we found the electronic charts to be precise. In Tonga miles out, Fiji a bit out, same in Vanuatu.
Mark 1 eye ball is the best navigation instrument in close quarters.