Vantaggi
The Clinic Assistant position is unionized (two mandatory raises a year, union support if you are unfairly accused of something, etc), the hours are generally consistent (although this varies by department), you get separate vacation time, personal holiday time, and sick time, 401k, very good insurance coverage through the employer. They typically hire very nice people.
Svantaggi
The usual healthcare cons. Specific to the company though, the union can also be a con because if you don't have enough seniority you can be "bumped" from your job (which means that under extenuating circumstances, someone with more seniority can take your job). This happened to me the first year I was there because a slew of (unionized) job positions were eliminated for budget reasons.