I enjoyed the Well of ascension, and thought it was a nice well-balanced sequel. Admittedly, it was a bit slow moving, especially compared to the first book. Much of the book revolves around the siege of the capital city, Luthadel, and the politics between the philosopher-king Elend Venture and various invading tyrant including his father. This aspect of the book reminded me a lot of the 2nd book from a song of fire and ice, and I keep picturing Venture senior as dopplerganger of Tywin Lanister. The drawn out siege and the inevitability of a climatic battle was a bit dull, and I also found this to be the case in a song of fire and ice.
But enough comparison and back to the positives. There are various side narratives in the book, that twist and turn just enough to keep you on your toes without seeming excessively frequent. Several times I had thought that I had "figured out" some incoming twist only to proven wrong. I also felt that the book excelled, especially compared to the first book, in its character portrayal and development. In the first book, I found some of the character a either wooden or like a caricature of a person. Perhaps controversially, I never liked the character of Kell, who died in the first book and so didn't annoy me here. For these reasons, I say the book is "well-balanced" as its main achievement is correcting failing in the first book, but it doesn't really excel the first book in energy.
if you enjoyed the first book, you should certainly read this.