Greg Bear, Gregory Benford and David Brin were the 'Killer Bs' of American SF in the 1980s and early 1990s and produced some excellent books between them, most notably Brin's Uplift Saga, Bear's Blood Music and Benford's Timescape. However, both Bear and Benford deviated into writing somewhat tedious scientific potboilers and near-future thrillers. Bear hasn't really done anything of note since arguably Moving Mars (itself not his best book) and Benford for even longer (despite the promise of the last four Galactic Centre novels). Brin still does good work but it's been a long time since his last novel now.
Perhaps Bear's mistake was that he was at his best when rewriting classic SF novels (Eon is a remake of Arthur C. Clarke's Rendezvous with Rama and Blood Music is very similar to Clarke's Childhood's End; he also did a Foundation book which was pretty good) and, when operating without a safety net, becomes a pretty ordinary author. The Forge of God is okay, Moving Mars is okay (overshadows by Kim Stanley Robinson's superior Mars Trilogy which emerged at the same time), Songs of Earth and Power is okay, Queen of Angels is okay, etc.
Interestingly, since the demise of the Killer Bs, American SF has been in the doldrums and British SF has risen much more dramatically to the fore (Hamilton, Reynolds, Morgan, Robson, Baxter, Banks etc).