I learned an incredible amount, and was treated as a full-time analyst by the end of the summer. Also got great exposure to the industry and high-level professionals in the firm.
Long hours, as is true in general with investment banking. Also, tasks / responsibilities became repetitive.
Advice to Potential Interns
You need to be dedicated to the work you do and have a true interest in the industry. However, this internship offers immense rewards to your potential career in finance.