I am in the process of doing maintenance on a Large Mach-II application written against the Mach-II 1.1.1 framework.
Since the Mach-II team has been so busy upgrading and adding new features, I decided the upgrade was compelling enough and I would work through any incompatibilities or backwards compatibility bugs. To my delight, I haven't found a single issue with the upgrade.
The application in question was written by developers who didn't have a lot of Mach-II experience so I am sure there are plenty of ways to optimize the application. Especially to take advantage of the Includes and Modules features. After all, the Mach-II.xml file is over 2600 lines. Peter Bell would roll over in his grave!
Also, while I do the necessary maintenance, I am going to roll ColdSpring into the application. The current Home Grown DI factory doesn't have quite the feature set of ColdSpring. I'll post any oddities relating to ColdSpringing the application as well
For more information regarding Mach-II 1.5 have a read at Dave Shuck's Blog about some of the new features.