Choosing between a top-up and a new loan

I have a currently running personal loan which has another 2 years before its fully paid back. I am in need of some more money. I am told that I can get a new Personal loan (my repayment history is good) or even get a top-up from the current bank on the existing loan.

Apart from the rates etc, what other parameters should I keep in mind. Which is better from a credit score perspective.

Any inputs would be helpful. thanks.