I had to Google 'YMMV' and my simple answer would be that I wouldn't use either!
A friend of mine recently bought the smaller George Forman Grill and then upgraded it for the larger George Forman Grill within the space of about 2 weeks. He is a big fan and swears by it. He bought it as an alternative to a BBQ but it doesn't offer the same benefits and takes up an awful lot of space.
I use a cast iron griddle which offers the same benefits as the electric grill albeit cooking on one side only, but also adds taste to the food characteristic of being grilled over coals. Its was cheaper, it's easier to maintain and doesn't take up space on my work tops.
Each to his own I guess.