MQSeries vs. MSMQ

In the messaging middleware area: What is the difference between IBM's MQSeries and MSMQ?

From a developer's point of view, both systems are similar in that they offer decoupled communication between processes, using message queues.

The main differences are:

• There are more large-scale deployments of MQSeries, than of MSMQ. Hence I would say MQSeries is more proven in mission critical systems.
• MQSeries runs on more than 20 platforms (including Windows2000). MSMQ runs only on Microsoft Windows.
• MSMQ is probably better integrated into the Microsoft development environment (VisualStudio, .NET)
• The following report suggests that the performance of IBM MQSeries is higher than MSMQ: http://www-4.ibm.com/software/ts/mqseries/library/articles/MQ5_2perf.pdf

I cannot say anything about differences in pricing of the two product, as I don't have MSMQ price lists at hand.