The best replacement for galaxy s3 is iphone 4s.

The best alternatives to galaxy s3 are rated as following:
★★★★★  iphone 4s
★★★★  iphone 5
★★  note 2
★★  htc one
★★  nexus 5
★★  iphone 5c
★★  moto x
★★  s3 mini
★  galaxy s4
★  galaxy s5
★  moto g
★  iphone
★  nexus 4
★  s4 mini
★  galaxy note
★  htc one x
★  lg g2
★  s2
★  galaxy note 3
  galaxy note 2
  galaxy mega
  galaxy s4 mini
  samsung galaxy s4
  galaxy nexus
  samsung galaxy s2
  galaxy s2
  grand 2
  i phone
  razr maxx
  htc evo 4g lte
  evo lte
  iphone 4
  htc one s
  xperia sp
  razr maxx hd
  droid razr
  razr hd

Your alternative for galaxy s3 is not listed? Suggest!
Speaking about galaxy s3, one probably shouldn't forget about jelly bean.

Other search terms related to galaxy s3 and their ratings are:

★★★★★ jelly bean
★★★ android 4.3
You have in mind a companion for galaxy s3 and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of galaxy s3 in all years. Click on graph for more.
galaxy s3
iphone 4s
iphone 5