David Brin, although one of the best proponents of 'hard SF', does have a tendency to make his books a little slow. The Uplift sequence ranges between very good indeed (startide rising) and very overlong (all the jijo books). Heart of the comet is a lot better than all of these. It seems that Benford has found a way to moderate Brin's style such that it is gripping the whole way through. This is a brilliant example of the closed environment SF book, and you really engage with both the main and subsidiary characters. Also, an interesting reversal of the normal SF genetic engineering vision, here they are an underclass rather than a priveleged elite. Definitely worth reading for all fans of Brin or hard SF in general.