Pros
The internship program is well established, especially at Abbott Park. Not only are interns paired with a manager, who generally acts as a mentor for the summer, but there are several intern-only social events run by the program. These allow for the interns to form a sense of community within Abbott in among themselves. Other events include a meet and greet session with senior level management from all divisions, a day of seminars on professional growth and ethics, and a dinner at the Abbott House where CEO Miles White speaks (and often stays for dinner and chats with the interns) and each table of interns has a VP or senior manager at the table. Networking is huge and is encouraged through the program. It's a great place to gain experience.
Cons
Expectations as far as working hours as not always explicitly stated and can be cause for either not enough time to finish projects or too much time sitting at the office for no reason. For permanent employees, there is little interaction with upper level management and the CEO, whereas the interns met him at least once over the summer. Abbott, like many employers, also tends to hire out of their current internship pool. Thus, if you intern with Abbott early in your college career but do not return to intern the following summers, the chances of you entering the Professional Development Program once you graduate tend to decrease.