* I would agree and disagree with Dan about this. *Obvious reasons
include expense (gyros are expensive), weight, and power.

Just so incorrect information does not get propagated I have to
correct this statement.
Gyros are no longer expensive (now less than $10), heavy ( 1 oz.) or
power hungry.
Solid state gyros are now found in most "smart" phones and many other
places.
The old mechanical gyros are dead in the water (except for some very
specialized applications.)