If you haven't seen it, here is a video of Epcot Forever on its opening night.
It isn't bad, and certainly not as disappointing as the show that replaced Wishes at the Magic Kingdom. I think die-hard Epcot fans will like it more than a casual visitor because of the nostalgia factor. So my guess is that the majority of Epcot's visitors will not be familiar with many of the tunes being played during the show. The overall music, though, is not as catchy and as spectacular/melodic as the original Illuminations - Reflections of Earth. But at least they incorporated, for my nostalgia benefit, snippets of Tapestry of Nations, which is my all-time most favorite Disney music.
There were anything spectacular with respect to the show itself, other than the kites. They were neat, but considering the number of cast members they have to employ during the show to do that, I don't see that one lasting for long, even if this is a temporary show. There are also a few "dead" spots during the show where nothing happens for several seconds. So the transition from one to the other was too obvious.
All in all, it isn't a poor replacement for Illuminations, but it isn't as good. Now they have an almost impossible task of coming up with something more spectacular next year when they replace this one.