I have a C80 and an older 2004 Navionics
card with Cuba charts. Our boat was used in south Cuba for 5 years with that card. Its fairly accurate for the south coast. However there is tons of uncharted stuff along the south western reef (around Cayos Bocas de Alonso). Talk to as many locals as you can, they know where the dangerous stuff is.
We also used CM93 charts to check their accuracy and they seemed "ok" as well.
Unfortunately, we didn't go anywhere else in Cuba so I can't comment on how accurate they are elsewhere.