I don't know about the fantom G, but I owned a Fantom X 61 for two or three years. It was a great sounding board. I had one expansion board which I installed. It had a lot of pianos and other sounds on it(and rhythms)which added to the board. It holds four expansion boards(which cost about $250 each). With all the expansions boards installed it is a monster, but you will have paid dearly. I was totally satisfied with one board installed.
It was well built and convenient to get around on. I llked the pads which could be manipulated to serve several purposes. I am sure, however, that the Fantom G must be better. I think most of the expansion board sounds are included stock. It has that large screen and mouse capability. They cost considerably more than the X.
If it a factor at all for your use, the Fantom X is light to port. It weighed about 25 pounds.