My origianl response to this thread/question has been adated to a separate topic on fitting methods.
Below are my thougths on the original subject.
Phil: You could usefully consider dcc as providing a feedback controller, optimally adjusted, right at the heart of the device you are wishing to control: ie inside the locomotive!
Each dcc module*/decoder can be individually tailored to appropriate maximum speeds, inertia, and starting voltage etc for each individual loco: so that as the controller is moved to 'step 1' (which could be one of 14,
27,28 or 128 discretely requestable speeds - to which the decoder will respond using maybe 256 internal speed steps, and changing with whatever inertia you have specified - from none to heavy) (*naming habit from Zero-1 days).If you want back-emf control, then this can be optimally provided, or not.
- its your choice. If you want directional lights, and integrated sound now or in the future, then it makes sense not to progress down a blind alley which prevents this being easily implimented (by remaining analogue)
If you are likely to modify your tracklayout, then 'classic' sectioanl wiring is cumbersome, and may require a new design of control panel, whereas with dcc just a paper drawing (or screen) needs to be redrawn.
If you already have sections on your layout - leave them, but just replace ONE of you analogue controllers with a dcc unit: and switch on as many sections as you wish that don't have an analogue loco parked on them (although 1 analogue loco can be controlled - but it would be via the dcc unit).
Modern h.f. decoders switch drive at above audio frequencies - allowing 'silent operation' and smaller components - suitable for all types of motor.
rgds phil