I have seen many many over the years, and for some reason I am always more impressed vocally with the US Phantoms over the London ones. The last London one that blew me away was Grant Norman and he was form the US.
I guess it is the way they sing the role or something.
all time Fav is Davis Gaines, then Howard, Richard Todd Adams, Tom J. O'Leary, Hugh, TMG, and eventhough alot of people hated Jason Mills, I loved his vocals.
I should also say that to me when it comes to the Phantom, a good vocal trumps good acting. I'd rather hear a Phantom that makes my knees go wobbly that one that acts briliantly with a vocal that grates my skin. I guess that also happens because I am usually sitting way up in the back of the theatre.
http://www.flickr.com/photos/27199361@N08/ Phantom at the Royal Empire Theatre