Well the only thing I "Buy" from them in the past few years is the my magazine subscription which are LESS than Amazon (today was the nook freebie Friday so technically you could say I bought it but it was free). And up until now I could still download them via the Nook for PC. Also Nook is more friendly than Amazon (magazine wise anyway if you are using a Fire) as far as converting and archiving.
BTW while it is possible to get a the books off of a Nook device, it depends on which one. The First edition was the best, but after they tend to put the books in a "hidden" partition and the only way to get direct access to the books was to root the device.
After last summer when they "upgraded" the SSL, it killed the Nook device I was using. While they released a update for it, I will have to reroot after and I just haven't bothered as of yet since I could still download my magazines through Nook for PC. Looks like I am going to have to now though.
Unless this Nook PC error is temporary.