I looked at everything that was available and just stayed with the free charts that are installed. None of the paid charts that were available had any better data for my area - mostly offshore Cape Lookout area. To be fair, I have not looked again in a couple of years but I don't think much has changed. The free charts are accurate and work great, but certainly not as much detail or fancy looking in terms of bathymetry as what you see with the Navionics charts, etc.