If you are happy at your current school, and are on track to graduate in 3 years, would you transfer to a significantly higher ranked school with a better program for your major and graduate in 4 years instead?
If your career goals can be achieved from your current U, and three years at your current U work out to be less expensive than 4 at the other, then there is no reason to transfer. Don’t forget to include the additional year of salary and work experience toward promotion in your calculations.