In terms of accuracy, all charts are fundamentally derived from the same government
supplied data. Marine
surveys are very expensive to conduct, and not profitable, so these are typically the exclusive domain of government entities (like NOAA and DMA in the USA). Private companies may provide some enhanced information, or different presentation, but the base hydrographic data is the same.
NOAA has moved to privatize the production of charts. They supply the data and private companies produce and sell charts based upon this data.
So, it really comes down to whose format you prefer and how you intend to use them. Maptech
makes some chart kits which are handy formats for small boat use.
Currently, for back up use, I purchase
full sized xerox copies of charts of the areas I plan to sail. These are less expensive than commercial
chart kits -- which can add up if you are covering a larger area. And, I print my own harbor approach charts from electronic charts -- handy because my routes and waypoints are displayed on them. This way, I've got detailed paper back up in case the electronics