Ok here is my disclamer I am not a sonographer I am a nurse practitioner for a radiology group and the director of a nuclear medicine school. I preform and interpret ultrasound examinations as part of my job.
Nursing does have more flexability than an imaging technologist (more nursing jobs
and more shifts). They salary is comperable between the two, sonographers can make more if on call or paid per the scan rather than by hour.
There is significant stress with being a sonographer including documenting fetal death, er patients, or cases ect... In addition there are a number of procedures you may need to assist with from transrectal prostate biopsy, paracentesis, amniocentesis, hystrosonograms....
But there may be down time between between cases. Unfortunatly iltrasound is operator dependant so a goos sonographer is a great find.
Occupational injuries are common sonographers develop arm and hand problems..... Depending on what part nursing you work in you can have back hand ect...
If you are introverted it can be hard at both jobs but there is always a way to find a job in a career field.
One interesting part of ultrasound is you can still have on the job training to qualify for certification(I am eligable for vascular and abdomen ultrasound certifications) so if you are really interested on ob ultrasound and nursing you might be able to be trained on the job with attending seminars or some courses.
Both are great career choices that offer decent pay and security....