I've changed the springs using a bar (safer with 2 people) and with spring compressors (pain in the ar*e as very little room) last time I used the standard wheel jack, it fits onto the body seam under the wheel arch and sits nicely on top of the suspension arm, a few tries to get the right place then it will wind down easily
and its much safer and easier to do it this way. I have never dropped the diff to change springs. 
... And therefor cant comment on which easier!
Sorry to be blunt but you see my point. Dropping the dif is far easier, safer and easily done with one pearson.
Dropping the diff is a slightly misleading discription to be fiar, it actually involves dropping the whole rear of the subframe. This is only attached by two dif blocks by the diff and the two bolts through the rear sub frame bushes. Just remove the dif blocks and the rear of the subframe hinges down by releasing the jack. Its an hours work iirc!
Plus, its all very well posting alternative procedures etc, but remember there differant levels of experience to take into account.
Follow the guide, its step by step, all you have ro do is follow it.