I have skied a '06 Allstar (178 or 76 ?) and a '05 Superspeed (182).
The Superspeed has no speed limit that I could reach (duh), a superb edgehold. It was also very heavy, very stiff and not tolerant of relaxed pace, short curves and skidding. A good ski foor bombing the groomers, but very 'uni-dimensional'. And physicaly demanding.
The Allstar is very close of the good points of the Superspeed, and is much more versatile and fun. It can carve small radius turns quite easily, can skid if necessary, will be more tolerant of technical mistakes. Much more lively and feels lighter too.
Those are very different skis, and I vastly prefer the Allstar. A really great ski IMO.
A search on this forum will provide lot of feedback on it BTW...