I don't think that the series ever really jumped the shark for me. The first two novels of the Excalibur trilogy was the low point for me. Unlike some of the other posters, I thought Restoration
was the best of the trilogy, and was pretty good in general. I will say I didn't care for the Beings storyline. I do however agree with a lot of others that Stone and Anvil
was the high point of the series, and while After the Fall
and beyond were never quite as good as S&A, I still enjoyed the series right up until the "end".