Just a comment about Panorama Factory, as I have used this fine program
for a number of very successful panoramas. It does have a small
learning curve; well, actually a trial-and-error curve. But, that is no
problem today with digital cameras at the ready to do a job over and
over until it is correct.
I have learned that a successful panorama should be a series of shots
not less than 22-1/2 degrees, or a total of 16 shots for a 360 degree
panorama. Better; take 24 shots, or even 32 shots. The more overlap, the
less distortion. And, mount the camera on a horizoned-level tripod
head. Don't depend on a steady hand and eye to guess where ends will
meet.
Panorama Factory does great for me.