delta 44, 66, AP2496, 1010LT all do a good job and since they are already working at max of 24 bits/96khz, what else can be much better than that?
the AD and DA converters they use are awarded for their quality and if you have good converters... that's giving the quality of a audiocard.
having more or less features, options, etc. are optional, not really necessary.

so, no surprize there really isn't another audiocard that would blow-out deltas. not yet.