Dan Rigsby has a really good comparative article on XmlSerializer vs. DataContractSerializer and also touches on the NetDataContractSerializer.
DataContractSerializer:
- it's fast - around 10% faster than XmlSerializer
- it's interoperable - works flawlessly with Java, Ruby - you name it
- uses explicit "opt-in" model - you need to mark what gets serialized
- doesn't require any constructor
- can serialize non-public members and internal fields
- doesn't support attributes on XML nodes
You tell the DCS explicitly what to serialize, but you don't have much influence over how it's done.
XmlSerializer
- serializes only public fields and properties
- serializes everything except those you exclude (opt-out model)
- support attributes and everything
- it's interoperable - works flawlessly with Java, Ruby - you name it
- requires a parameterless constructor for deserialization
You tell the XmlSerializer pretty clearly how and what to serialize, but you cannot serialize everything - only publicly visible properties.
The NetDataContractSerializer is a bit of an oddity - it's not interoperable, it works only if both ends are .NET - it includes .NET type information into the message (making it bigger). You cannot add it declaratively to a WCF service "out of the box".
It's a tough trade-off - as always. Definitely stay away from any binary formatter - that's not backwards compatible, brittle, and bound to give you headaches - use one of those standard ways of doing it. Which one is the "best" for your given scenario is really hard to tell - you'll have to figure that one out for yourself....
