One my co-workers tells me that in 1.1 it's more appopriate to use the ActionMessages class over the ActionErrors class. Can somebody provide more information about this change, or where to find more details?
ActionMessage is a super of ActionError. ActionMessage was added in 1.1 because the name ActionError implies that it shouldn't be used for general information or warning messages. So I guess that it makes you "feel" better using ActionMessage. The ActionMessage is used exactly like the ActionError except that it can represent a less severe message that needs to be displayed to the user. So it's only more appropriate.... if it's more appropriate!