Transmission flush good or bad idea?

I have a 2002 ford Taurus i bought a few months back. lately ive noticed it will slip a little while shifting. i got all the service papers from the guy i bought it from and it seems the last thing that was done to the was a filter change about 52,000 miles ago (at 123,000 now). Ive heards great stories and horrible shorties. i dont want to have it change and the go out a for monthes later because of the change. any suggestions on what to do?