Hi David, I think you will find the Massoth system pretty easy to use, at least for the basics - you really don't need to get into the complexities of CV programming unless or until you really want to. If your present locos are all set up and running happily on your MTS2, then you will pretty much be able to just plug all the Massoth kit together, select a loco number and it should all work just the same as you are used to with your MTS controller. The whole CV business only starts to be necessary when you want to start fiddling with things and changing factory settings, if you're happy to run your locos with their factory programming then you really don't have to worry about them.
All your exisiting LGB modules, switch decoders, reverse loops etc should also work just fine, once you read through the Massoth manuals a couple of times. The instruction manuals can seem a little daunting at first glance, but if you managed to set up all the modules for your MTS then you really shouldn't have much trouble doing the same with your new Dimax.
When I moved from MTS2 to Massoth, I found the transition very straightforward - I really don't think you'd have many problems, and there are plenty of folks on here to help with any that do crop up!
Jon.