Are there any advantages of using NServiceBus over simply using the .net driver for RabbitMQ (assuming we can replace MSMQ with AMQP). Does NSB provide any additional functionality or abstractions that are not available directly in AMQP.
Main advantages include (but are not limited to):
These are things, that you'd need to roll yourself, if you were to use the RabbitMQ .NET client directly - unless, of course, you don't need any of these things.
Oh, and if you use MSMQ instead of RabbitMQ, you can get all these things in a broker-less model :)