Choosing an ESB for .NET

I know that the question has been asked before, but it's been two years and things might have changed. Also I have more specific requirements that I wish to discuss.

We have a few system开发者_运维百科s that need to interoperate. We want to use the Mediator Pattern and a Publish/Subscribe communication model: Some systems will publish information to the ESB (the mediator) that will in turn push the information to the subscribers.

That is basically all we need but that will probably involve some type mapping and require communication with various protocols. At the moment we have WS-* (WCF) services and REST services.

I am not familiar with ESBs at all so I guess my first question should be: will an ESB help me achieve this? If it will, I'd need to select a product with the following criteria:

1. .NET based and preferably open-source
2. Easy to use I feel that an ESB can do much more than what we will really require. I don't want to be lost in heaps of features and I'm also worried of the overhead that there might be when setting up / coding against an ESB with too many features.
3. Widespread Ideally I'd like to use something that is used by more people so that I can get help if I need to

I am also curious to see how BizTalk would compare and whether it is free, included in any MSDN subscription, or what the cost would be.

Thanks.

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I can only really comment on BizTalk

• BizTalk certainly isn't free
• As at BTS 2009 it is (mostly) .NET and has full support for custom .NET assemblies
• It is integrated with the VS IDE and is relatively easy to use (subjective of course)
• Pub Sub architecture can be achieved nicely using DirectBound ports via the MessageBox
• There is considerable support for it (around 10 000 customers worldwide)

However, IMHO BTS is more suited to high value integration work such as EAI, Business Process and Business Metrics.

Alternatives / complementary products that we have considered:

• NServiceBus - Open source
• Managed Services Engine - For virtualizing, versioning and managing (lots) of SOA services

HTH