The best replacement for gh3 is g6.

The best alternatives to gh3 are rated as following:
★★★★★  g6
★★★★★  gh2
★★★★★  gx7
★★★★  gh4
★★★★  70d
★★★★  5d mark iii
★★★  rock band
★★★  bmpcc
★★  em1
★★  7d
★★  blackmagic pocket
★★  c100
★★  ghwt
★  omd
★  ghs
★  5d mark ii
★  em5
★  af100
★  gh 2
★  gh
★  5d markiii
★  bmcc
★  5d
  world tour
  black magic
  rx10
  omd em5

Your alternative for gh3 is not listed? Suggest!
Speaking about gh3, one probably shouldn't forget about atomos ninja.

Other search terms related to gh3 and their ratings are:
★★★★★ atomos ninja
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Google Trends

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gh3
g6
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