I bought a licence copy of Memory maps Quick Charts of the East Coast, which gives me a full overlay of all the marine charts for the east Coast from Portland in Victoria through to Mornington Island in Queensland. Its the same charts as issued by the Australian Hydrographic Office, and the same as the Hydrographic Office own CD of charts with additional features.
It gives me to ability to make customised charts for trip planning, I can plan routes, import data from my GPS and upload maps into a tablet or mobile phone or print them off.
Navionics have a app for both Android and Apple devices, but without the ability of to directly print them off, but i don't know the source of their charts.
The alternative is to purchase the actual paper copies of the charts but since they cost around $25 ea that becomes expensive.
I must admit that the Navionic app charts on screen have better colours.
for Toppo maps I use Locus Pro for android devices, the advantage is that I was able to up load all my Garmin GPS data, routes, way points etc into it. but its has poor data for coastal areas.