Pros
There's a lot of potential opportunity for learning and advancement, along with exposure to other areas of the payment card industry. Elavon makes a great springboard into the rest of your career. They're rapidly expanding their areas of interest, so unless you're in the Operations section, there's a lot of new stuff coming down the line constantly to challenge you.
Cons
There's a lot of office politics, and the company as a whole is extremely conservative in its approach to new concepts and processes. This can be frustrating as there's a tendency to cling to archaic and outmoded ideas. Working in Operations is largely thankless and a miserable experience - the customer service side in particular. Management doesn't really have a firm grasp of the job their employees do, and displays a habit of managing people as metrics instead of employees. Pay is not competitive. In general, expect to be underpaid just for the job you're doing, much less for what your resume and experience command.