The best replacement for 16gb is 32gb ipad.

The best alternatives to 16gb are rated as following:
★★★★★  32gb ipad
★★★★  32gb iphone
★★★★  32gb
★★★  32gb tablet
★★★  32gb iphone 5s
★★  32gb ipad air
★★  32gb ipad mini
★★  32gb nexus 5
★★  32gb ram
★★  8gb
★  32gb nexus 7
★  32gb kindle fire hdx
★  32gb ipad 2
★  32gb kindle fire
★  64gb
★  32gb iphone 4
★  32gb new ipad
★  32gb iphone 5
★  64gb ipad
  8gb ram
  32 gb
  32gb ipad 3
  32gb nexus
  32gb ipod
  8gb iphone
  ipad 32gb
  32gb galaxy note 10.1
  8gb iphone 3g
  32gb kindle
  32gb ipod 5
  iphone 32gb
  8gb ram gaming
  32gb memory
  8gb video editing
  8gb ipod touch
  32 iphone

Your alternative for 16gb is not listed? Suggest!
Speaking about 16gb, one probably shouldn't forget about retina display.

Other search terms related to 16gb and their ratings are:
★★★★★ retina display
You have in mind a companion for 16gb and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of 16gb in all years. Click on graph for more.
16gb
32gb ipad
32gb iphone