Originally Posted by: MaerklinLife 
Originally Posted by: H0 
because mfx has a design flaw (confirmed by ESU - Märklin will probably never admit that) and mfx uses weak feedback signals that can easily be disturbed. [...]
I have seen this mentioned a couple of times. Can you elaborate on the details of the design flaw?
The idea behind the Central Station is easy: you put the loco on the track, the CS reads all CVs from the loco and this takes a minute or two.
If you later want to change any CV, the dialogue opens without any delay as the CS already has a copy of all CVs.
Now run the loco on a different layout. When the loco comes back, there is no way for the CS to know that nothing has changed - and all CVs will be read again.
Delete a loco from the database - and all locos that are not on the layout at that time will be read again the next time they get contact to the CS.
The CS2 uses a different approach: to drive a loco, only the basic CVs are read and the delay is much shorter. The delay comes when you want to change CVs. Every time you want to change CVs.
You can make a test-run while still in the CV screen - and you should do that to avoid the repeated delay if you later have to make more changes.
So with both CS1 and CS2 I have to follow strange rules to avoid unnecessary delays imposed by the wonderful mfx protocol that is supposed to make things easier and save time - I consider mfx a waste of time.
A simple change counter that is triggered with every CV write would allow CS1 and CS2 to keep their local copies of the CVs in sync without reading them again and again and again ...
DCC is stupid. DCC just reads the CVs that are going to be changed. Simple, fast, efficient.
Several times I told the story of the failing mfx registration at a club meeting. After some investigation we found that a Märklin coach set with interior lights disabled mfx registration for all locos. When we put a new mfx loco onto the layout, I just put a piece of paper under the centre-rail slider of the lighted coach set. After the registration, the paper could be removed again.
Simple solution - but it takes minutes of trial and error before you come up with that simple solution.
A Märklin coach set prevents Märklin locos from registering with a Märklin controller. Great system.
Originally Posted by: MaerklinLife 
And with regards to the RailCom cut outs, I assume that this issue really is a non issue because if you make true use of RailCom you would want all your locos to have it.
You can use some locos with RailCom for automatic operation while running locos without RailCom manually. Or use RailCom for programming on main for locos that support it. Or use RailCom+ for automatic registration of newer locos while older locos are registered manually.
Are all your locos mfx? To take full advantage of mfx this should be the case ...
I have dozens of locos with DIP-switch decoders and I intend to keep them as they are - no mfx, no RailCom.
It's different if you want to take advantage of new decoder features on your layout - ABC braking or absolute braking distance come to mind. But even with that scenario you can have automatic operation with newer locos (maybe on the mainline only) and manual operation with older locos (maybe on the branchline only).