|I never use fractional binary.  I've always used fixed point binary,
|known as scaled integer and manipulated accordingly....

|Do the people who use fractional binary have some reason that outweighs
|the scaled integer option?  Is there some feature of the PIC instruction
|set that lends itself to fractional binary over scaled integer?

Fractional binary is simply a special case of fixed-point or
scaled-integer binary in which the unity point is located between
to machine words of the number; e.g. an 8+8 bit fractional binary
number is the same as a 16-bit number scaled by a factor of 256.
Since scaling by 256 (or 65536) is easy, fractional binary can be
quite handy.

Note also that conversion of a fractional binary number to decimal
is somewhat easier than the general case of binary-to-decimal conv-
ersion since it requires multiplication by 10 rather than division.

Finally, FYI, the Motorola 68HC11 actually does have an instruction
for fractional division.