Stayed at both several times : the Hampton is in a great location for the city centre, the railway station and the metro, but doesn't have anything particularly notable about it.

The Hilton is on the other side of the river in Gateshead, and IMHO is the better option if you have Hilton elite status. The lounge has great views of the riverscape and bridges, as do the nicer rooms. It's a very agreeable walk over one of the bridges back towards the city centre, and only takes 10-15 minutes. You're also right there for the quayside too.