I owned an early dCS stack, which was non-firewire. I had the Elgar and the Purcell.
I now have the dCS Puccini (currently without clock). Personally, I think that the dCS Puccini is an improvement over the original stack, for the following reasons;
1.) It loses the slightly dark, slightly cloudy sound of the Elgar.
2.) It sounds more dynamic and alive.
3.) It sounds "cleaner" and clearer.
4.) It extends further in both bass and treble.
If the Elgar is better in any respect, it is in a sense of depth (uncommitted on this point).
I should stress that it may be that there may have been improvements that made their way into the Elgar plus which change that equation.
I now have the dCS Puccini (currently without clock). Personally, I think that the dCS Puccini is an improvement over the original stack, for the following reasons;
1.) It loses the slightly dark, slightly cloudy sound of the Elgar.
2.) It sounds more dynamic and alive.
3.) It sounds "cleaner" and clearer.
4.) It extends further in both bass and treble.
If the Elgar is better in any respect, it is in a sense of depth (uncommitted on this point).
I should stress that it may be that there may have been improvements that made their way into the Elgar plus which change that equation.