I thought the book was great. I must admit that I haven't read much science fiction in recent years. The science fiction I most enjoy are works by such authors as Arthur C. Clarke, Robert Heinlein, Robert Silverberg, Ray Bradbury, Phil Farmer and Asimov published in the 50's, 60's and 70s. I read these authors in my high school and college days (more than a few years ago!). More recent sci-fi I haven't really cared for - especially the glut of fantasy novels that seem to dominate the field these days.
"Gods Themselves" kept me interested clear through. After reading the dedication, I was hooked - Asimov accosts Robert Silverberg at a sci-fi convention for referring to a radioactive isotope (plutonium-186) that could not exist. He then tells Silverberg that to show him real ingenuity, he would write a story about it (leave it to a biochemist!). This story ended up as "The Gods Themselves."
Not only was Gods Themselves great sci-fi but Asimov gave some great commentary on our times as reflected in the characters and situations he created in the 1970s. This included the ambition of Hallam in the first section. Rather than relinquish any of the credit for being the father of the "electron pump" he would risk the annihilation of the planet. Implications of the electron pump also mirror our current problem of global warming - mankind has ignored the consequences of burning fossil fuels for energy to provide for human comforts (did Asimov foresee this?). The second section was perhaps the most enjoyable part of the novel in which Asimov creates a unique alien "para-universe" including the "triplet" sexual relationships of the beings (the aliens have three sexes with fixed roles for each sex - wow!). And finally, the third section provides a satisfactory resolution to the story. All in all - sci-fi at its best!
Probably the best single novel that Asimov ever wrote.