I personally can't see past the Fiesta ST in that price range for a car with performance. Had mine for a month and a half and I don't regret getting it for one second.
It's not really comparing like for like though is it? No arguments Fiesta ST is a good little car but it's hardly in the same price bracket. Up Gti starts at 13,750 ish but the starting point for the Fiesta is 16,595. Given Ford are generally more generous with the discounts it's still going to be more. I'd say the New Polo R-Line vs Fiesta ST would be a closer comparison.