The only problems removing the brake drums using the 4 bolt method are:
If you have ABS brakes you need to disconnect the ABS sensor at the control
arm and work it through the backing plate. If you damage the cord - you will
have to replace the whole hub assembly.
The 4 bolts are generally rusted or frozen on the hub and an impact wrench
is required to remove them without snapping the heads off. Snap the bolt
heads, new hub required.
To gain unrestricted clear access to these bolts you will have to remove the
shocks.
You should really have the car on a hoist if you use the 4 bolt method.
And in most cases the drums will either have to be replaced or trued up when
the rear brake shoes are replaced any how.

In 2000 when I bought my North American Focus I was told by my dealer
service tech that the only way to remove the brake drums was using the 4
bolt method, when the time came to replace the rear brake shoes the Tech
removed the drums using the hub nut method. I believe its a 29 mm socket. I
asked him why and the response was the above noted problems.

"

I took mine off using the four bolt method and didn't run into any problem
with frozen bolds or access to them.  They were torqued very tightly and I
had to tap the wrench with a hammer, but they yielded readily.  Nor did I
have a lift, just a hydraulic jack from Wal-Mart (about $15.00) that fits
under the rocker panel just as the Ford jack does, but is more stable and
has a safety pin keep it up if the hydraulics fail.   If you have ABS you do
have to thread the electric cord through the hole in the plate, but that is
easy.  Of course, you also have to undo the plug first.  But don't forget to
plug it back in when you get done!  The hardest part of the job is none of
the above, but putting the springs and shoes back on the plate.