alt Hacker NewsI agree it's a difficult problem. For scifi, I usually look for Hugo or Nebula winners, but also word of mouth and recommendations.
Never Amazon! I also don't know anyone who goes to Amazon to look for book recommendations, but that might be my bubble.
I buy a LOT of books in brick and mortar stores, my preferred method of browsing books.
Yes unfortunately any system can be gamified once the incentives are there: Best wine, best movie, best album, best keyboard, best monitor, the list goes on. Hugo or Nebula winners, and any other "winner" for that matter are usually actively sponsored and artificially pushed onto the nomination lists by their publishers/influencers/etc, there is just no way the judges can read the 1000's of novels that come out each year.
Occasionally indie authors beat the system like Andy Weir with the Martian, but that took both good writing and a lot of traction from his online community for it to go viral and for it to get recognition.