unrolled cores are not necessarily crappy cores.

all we care about is the GH/s...  we don't mind whether they achieved it from rolled or unrolled hash engines.

some implementations will do better with rolled cores and some with unrolled.  depends completely on the design.

with rolled cores you can cram more of them on a die, but run at a slower speed.   with unrolled, you can run at a higher clock speed, but fit less of them on a die.   either of them could be better... depends on many factors, but the bottom line...  Performance, Power consumption, and Cost... are what we care about.   And much of that can be expressed as a GH's / Die area, that would give you a measure of efficiency - or in its simplest terms, GH's/S. per square mm of die area - at least when comparing like for like (all 28nm's for instance)

-- Jez