In a vehicle over 50k miles with no prior flush, many technicians suggest dropping the pan instead of a flush- they beleive the flush exposes the tranmission to failure after the flush.
For me-neither flush or dropping the pan. I do a systmatic siphon of trans fluid out of the trans dip stick three times over a two week period. Very simple and easy on everything. One issue with my method would be if the filter is clogged.