Ronan was the best by a mile, Adele was a great choice of song and he sang it beautifully. He comes across as a decent, cute and well educated young boy as well who held his nerves well and didn't crumble in the form of crying to the pressure like most of the younger acts do.
The piano guy deserved to go through as well as he has more talent and can do more with his act, although the bike guy and the judo girls were impressive. Other than these acts, the rest of the acts were very poor in what is a very average series. Ronan to win.