Decisions about switching internships

I currently have a job at Thomson Reuters Pricing Services. My position there involves a lot of data entry and essentially is data operations. I'm looking at prospectuses all day and making sure our system matches the terms on the deal. However, I recently received an email from an old connection who offered me a position at Instinet (a Nomura company) at the sales and trading desk. I personally want to be working front office for obvious reasons but I don't want to leave Thomson Reuters only to realize that Thomson Reuters is a better company that will look good for future employers once I graduate. I was hoping someone on here would have some insight on which position/company is better for personal growth and which looks better on a resume at the end of the summer. Thanks!