Choosing between two roles - JPM/UBS

Long time lurker first time poster, in need of some advice.

I've recently received two offers, one from JPM and UBS and I'm having difficulty choosing between the two and the future career progression prospects attached to both. The aim is to ideally progress into a front office role and both the roles on offer are trade support, so wondering which bank/role offers the best route for this.

The role at JPM is as a trade services associate sitting within the credit (exotics/hybrids) trading team. 

The role at UBS is XVa Trade Support, sitting within the derivatives and treasury function.

Its been emphasised that both roles have extensive exposure to the FO traders and it is a requirement to work closely with them. Which of the two roles would be the better fit to progress into a direct FO role, and which would be the better bank to join?

To give you guys a bit of background, I'm 26, hold a MSc in Finance and have done internships on the buy side, a 18month grad placement on the equity sales and trading desk at a European bank and more recently have worked in Prime Brokerage Sales for a boutique.

Sorry for the long story and CV. Any guidance would be appreciated.