I have only used their serial RAM and never had a problem.

Some months ago we started to use complex Ramtron derivative FM3164. This part contains nonvolatile RAM, RTC, Power SV, Watchdog, Early Pover Fail detector and other features.
That is rather typical, when a company first ventures into uncharted waters the first few products usually end up with the errata being more pages than the datasheet.
I have been there, done that. The REAL problem with cases like this is manufacturers honesty. I will not and never will use Atmel, because when i used their very first '51s they refused for about a year to acknowledge a problem with the chip. I would still use a new product from someone else, but not in a large quantity production.

Erik