I applied through an employee referral. The process took 1 day. I interviewed at UBS (New York, NY) in May 2012
Interview
I was brought in through security, HR and then to the hiring manager. We met in an office where we had coffee and chatted like old friends. I was asked about my background, my goals for the job, and if I had a story on my greatest achievement and my greatest mishap.
I was asked first behavioral questions such as why I want to work there. Followed by asking me to take me through my resume highlighting my education and previous internship experience. Following this I was asked technical questions involving the prices of highlighted volatile stocks. Overall the interviewer was extremely friendly and helpful.
I applied online. I interviewed at UBS (London, England) in Jan 2015
Interview
Phone Interview.
I applied online. The process took weeks. The interview was bod standard, and so too was the aptitude tests. :)
Just know your own competencies inside out and you should be fine.