Acceleration/deceleration is optional with DCC. You can configure the decoders to start/stop instantly (rather unlike the prototype). I haven't set acc/dec on mine as it makes it easier for my children to operate it.
Very much worth it for me. My children can drive trains where they want without needing to know about the magic done by the auto reverser (reversing loop), or managing which sections of track have power or which controller is currently connected to which section of track. They just select the number of the engine and away they go. Percy, Thomas and Gordon et al all have numbers well known to children, so even 5 year olds can manage this. It does mean that engines can run into each other, but somehow they don't see that as a disadvantage.
The discussion on what the Hornby Select may or may not do is a bit curious, especially as most of the participants don't have one (and are unlikely to get one). I suppose it reflects Hornby's position in the UK market. My wife refers to the layout and trains as the "Hornby" even though the track is Peco, the controller is Lenz and half the locos are Bachmann. Rather like our Hoover (made by Miele).
Mark Thornton