Hi,
I have completed my undergraduate studies from Electrical Engineering Department, IIT Kharagpur, India. After graduation, I worked as a research assistant at UW (three months) in the field of computer vision and at UPMC (three months) in the field of biomedical image analysis. I got the PhD offer from my mentor at Pitt. My research interest is in image processing and computer vision. I am not sold on the specific area of the research and would like to explore this field. You are correct at pointing out that UPMC will limit my research to medical images but it has the following advantages:
I have fully funded GSR offer from the supervisor under whose guidance I have already worked. UPMC works in collaboration with CMU which is one of the best in Machine Learning and Computer Vision, so I have the benefits of taking courses, attending seminars, networking etc. I have two supervisors who are affiliated with UPMC, Pitt & CMU and I am comfortable working with them.
On the other hand, UCSB has not yet provided any financial aid documents. Given that, I will have to TA the courses for two quarters or so. I understand that going to UCSB, I will be able to explore the research field before adhering to a specific field or supervisor. Also, UCSB ranks among the top ECE Departments in the world. I am from EE background and a little skeptical about how bioengineering department would treat me.