Denise Linn's book has a gentler tone to it than Karen Kingston's book. Linn is more flexible in what she considers appropriate for clearing space. She emphasizes that it's more important that you be comfortable with your tools, than that the tools be made specifically for space clearing. Kingston differs from Linn's approach in that she is more particular about the tools used. This may be explained by her more limited background in such work, whereas Linn has had a wider education in such arts.
Kingston's work is very influenced by the Balinese, whose culture she is immersed in for a time each year. From what Kingston describes, the Balinese have a beautiful culture, with time honored traditions that are tied directly in to the energy of the land upon which they live. Kingston has taken inspiration from this culture, and uses what she has learned from the Balinese in her space clearing work.
Linn's work appears to be a more eclectic mix, with influences from diverse ethnic groups that include the Native Americans, the Aborigines of Australia, the New Zealand Maoris, and the Zulu People in Africa. Linn also gives credit to her past spiritual teachers, including a Hawaiin Kahuna.
Both books are very useful, and have a lot of very good information in them. I prefer Linn's, but I have also found that Kingston's book has merit. I utilize techniques from both with success. Linn's book is essential reading for me, with Kingston's being good for added emphasis.