Need help choosing between two offers

I received two offers for a Finance Internship in London. The first is to work in the Finance division at BlackRock and the second offer is to work in the Finance division at Barclays Investment Bank. 

They're both offers for a Finance Summer Internship. I like the culture at both firms. However, i am not sure whether working in the Finance division is better at BlackRock or Barclays in terms of career development and compensation. Does anyone know about this or have any useful insights to share please? For example if working in the Finance division will allow me to progress in one firm faster than the other or if one firm pays more than the other etc. 

Thank you! It would really mean a lot