I've read at least one book by all four authors. As the world's leading authority in what I like
, here are my conclusions.
In the "yes" camp:
George R R Martin - Enormously influential, and pretty great, but unfinished. I think waiting for the end is a foolish exercise, given that it's already out there influencing everything, and the first three books, especially, will always be excellent even if the next book is "and then he woke up, and it was all a dream."
Robert Jordan - I admit that it's a pretty long time since I actually read one of these (I haven't read the last three books, by Sanderson), and a colleague, who is re-reading the whole series at the moment, says they start out kind of YA-ish, but it's a decent enough series that starts strongly, and (I hear) finishes strongly, with a bit of a sag in the middle.
In the "no" camp:
Terry Goodkind - A (different) colleague of mine who shares similar tastes discovered this series a few years ago while on holiday, and came back raving about how great it was. I borrowed the first book from him, found it a bit obvious and uninspired, and didn't read any more.
Steven Erikson - A lot of people really love this series, but it just didn't work for me. I had a lot of problems with the first book. I did eventually finish it, after taking a break to read something else, but have no real inclination to read the second one. I didn't much like any of the characters, or understand their motivations. Several elements seemed to be retconned after the fact as the book went on. There was an arms-race of ever more powerful beings that just became a bit laughable. There are whole plot strands that just end up nowhere. If all you have are explosions, then explosions become surprisingly uninteresting.