Database Encryption?

Hello to All, I have been tasked to research companies that provide database encryption within the database. Data at Rest. I was hopeing someone out there is using database encryption to protect either critical customer information or sensitive company information in informix. Or database encryption against another RDBMS. Some of the companies I have come across thus far are Protegrity, RSA Security, Application Security, Eruces, ...etc. The only company so far to have claimed support for informix was Protegrity, however, since IBM acquired informix they say they are no longer supporting informix (yes, another vendor that doesn't know the future of informix). Anyway, information received indicates that Protegrity is performing a restructing and may not be stable, this leads me to my questions.... Who out there is using database encryption for their data at rest? Who's software are you using? (if you are using Protegrity please respond with your experiences) What are your experiences with database encryption? Any assistance would be greatly appreciated. Thanks