Due to time difference, I didn't watch the livestream. But I watched four finals clips in YT of the acts that I care about--- Jai, Ronan, New Bounce, and Michael Collings.
Both Jai and Ronan were a bit off in the finals. Probably because of nerves of being in the finals, or lack of practice due to the short gap between the semis and the finals, or maybe both.
Jai --- I love "To Where You Are", have loved it ever since I first heard it sang by Josh Groban (though I don't know if it's his original or not). But I don't like that BGT arrangement one bit. It was hurried, and the lyrics were cut in a way that just doesn't work for me. They brought in the choir to bring in some sort of majesty, but in my opinion, that could never have replaced that of just Jai, alone, singing the song in a phase and build up that was in the original. Not his fault of course (they had limited time to perform), but "To Where You Are" just didn't work as a 2-minute song.
Ronan --- It was a nice song choice. Certainly something that can be pulled off in under 2 minutes. But I don't think he sang it particularly well. At least not to the level that I expected after watching him in the audition and the semis. The rendition didn't show his control of his wonderful voice like his audition and semi-final pieces did. It sounded strained. Perhaps he overworked his voice during the practices.
New Bounce --- They were more consistent from the semis to the finals than the two I described above. But I thought they should have chosen something livelier, like the one they sang at the semis. Their finals song choice didn't have that wow factor, or that bringing down the house factor, that they had in the semis.
Michael Collings --- Another consistent act, from the audition to the semis to the finals. But I think singing the same song that he sang at the audition hurt his chances. Which is unfortunate because I thought among the four acts that I followed he was the most consistent one. He seems like a nice guy and genuinely loves singing (probably to his wife and baby). He should have sung a different song. There's a clip of him singing Hallelujah in YT. He could have sang that.
And that's my four cents, on the four acts that I followed in BGT, thanks to
Yorkie and his video sharing ways (even if he slacked at the end).
And yes I can be a sour whine when it comes to these talent shows... 
