My controller supports MM, DCC, and mfx (plus SX, but this is disabled).
This allows me to take advantage of (almost) all DCC features while I still can use locos with MM decoders. Therefore I had no need to upgrade all locos.

Mike,

it took me a long time to decide which controller to buy and my last option was between ECoS and Zimo. at the time Zimo didn't have any sound decoders and all of my Märklin locos had been converted with a 5 pole highefficiency motor and an ESU lokpilot/sound decoder, as you know previous Roco locos had all ESU decoders.
As Ray said MFX gives you 16 functions and ESU has 21 function available but I think Zimo has gone higher than that.
ESU has recently introduced an upgrade for the 6021 when used in conjunction with an ECoS so you can access 16 Aux functions over 4 different decoder numbers.
I don't know how you upgrade a HAG loco to digital and I'm not familiar what is available for Hag to do a conversion to digital.

My main concern was always if Märklin, ESU or Zimo upgrades their protocol am I left with decoders I have no use for it any longer and you've mentioned Zimo decoders not responding to the Lokprogrammer (although I've heard you can program the first 6 CV's).
Zimo at the time wasn't geared for Märklin 3 rail and in meantime had changed its policy regarding upgrades (they are now free of charge) and had a lot of upgrades (mainly bugs) in their decoders) or control unit.

Märklin introduced the CS 60212 and now we up to 60215, ESU had 2 changes from black and white to colour screen and Zimo I'm not sure.
The ECoS supports these systems as Tom mentioned.

I don't know what the future holds and to some it may not be an issue but if you have 200 or so locos it makes a difference which one to choose from and secondly what the majority brand of your locos are, e.g. Roco, Hag or Märklin, Roco again earlier locos had the 8 pin socket and the new ones most probably have the 21 pin socket. earlier Märklin digital locos never had the 8 pin socket and they've started with fixed decoder boards and still do except the decoders with 21 pins but they also have light (globe and not Led) attached to the board in steam locos tender.
What I've seen so far from your collection they are mainly electric locos.

Who knows which way Märklin is turning now the company has been bought by another company and who knows who is left who has the expertise to guide the new company to higher levels with their digital components but all in all past changes showed they are innovative but any command station from any manufacturer would have to be something extra special for us to change over to something else again and what we've got so far is maybe enough for us to stay with.

however, if you go down the path of a personal choice and follow the latest loco cab console illustration and want to know how much fuel you've got left in your diesel tank but you haven't got a diesel fueling depot on your 1.2m x 1.2m layout, the whole concept of a layout with scenery may become irrelevant and the focus may be switched from seeing you locos run on your layout to a driver who is fully occupied with drivers cab instruments to keep the locos running in a digital created operating mode.

John

Mike,

I only can give you information about the ECoS, the ECoS will recognize 255 (short address) Märklin Motorola addresses, so you can programm all your Märkklin/Hag locos within that range, all your DCC locos you can program from 256 onwards, e.g. Roco or locos which have been converted with ESU decoders (long addresses). your 6080/6090/60901 decoders would be all 1-80 address and the ECoS has reserved 255 loco addresses for the MM protocol anything above would be classified as DCC
for instance you have a Roco loco with an ESU decoder and your prefered loco address for this loco is 254 it will come under the Märklin motorola protocol and you can achieve 14-28 speed steps anything above and including loco decoder number 256 will be 28-128 speed steps.
For me this is a bit annoying as I do not have any Märklin locos with Märkllin decoders but I've managed to re-arrange my locos.
The ECoS automatically recognizes the type of decoder hence the configuration 1-255 any decoder you've mentioned can be set from 1-80 and you have to remember which decoder number it has to type in the corresponding decoder number (lokprogrammer) but at the same time you can manually register the loco on your EcoS with a photo and the decoder number so in future you'll be able tell which loco is which.

I think you're aware of it, ESU M4 decoders have the same characteristics as a MFX decoder the difference is you can change all CV's and program them and being a Märklin related protocol it has only 16 sound functions instead of 21 for an ESU decoder and I think Zimo is already up to 26 functions.
the CS 2 recognizes MM, MFX, DCC as well.

John