I use WeatherEye (free)
I tried TWC but the UI is a bit clunkier and uglier, IMO.
for example to check weather for another city in TWC you have to first click the location button, then click a second time on your choice, vs WeatherEye or the built in weather app where you can simply swipe to flick through all your favourite cities - much faster and more convenient. If you only care about 1 location, then this won't matter to you, but it's a big difference if you like to easily check several cities.
The screens are less cluttered and better formatted in WeatherEye than TWC too, making it easier to at a glance see what you need - has something to do with their choice of fonts, colour and layout.