I rotated into PO the first year. I was very young at the time and it was exhilerating to have that power. (26 years old is too young to even be an elder, most cases)
The trouble with the rotation has already been addressed, but to summarize, what happened is there always seemed to be the wrong men in the wrong jobs all the time.
Later years, when I was a PO by appointment rather than rotation, I set a goal that after 5 years, I would step aside as PO and do another job. I always felt that power tends to corrupt and I didn't want to get in a position that I was 'wielding power'. So, at 5 years I resigned. I was glad to do so. I felt it was better for the body of Elders and the cong to have the variety, but I do feel that 1 year was not long enouhg for a brother to really learn his responsibilities.
The rotation really was a nightmare, but the continuous PO in one person is likely worse.