The best replacement for sodastream is soda siphon.

The best alternatives to sodastream are rated as following:
★★★★★  soda siphon
★★★★  seltzer bottle
★★★★  perrier
★★★  soda club
★★★  isi
★★  cuisinart
★★  sodasparkle
★★  primo
★★  oxfam
★★  penguin
★  flavorstation
★  siphon
  syphon
  flavor station
  sodaclub

Your alternative for sodastream is not listed? Suggest!
Speaking about sodastream, one probably shouldn't forget about coke syrup.

Other search terms related to sodastream and their ratings are:
★★★★★ coke syrup
★★ mio
★ torani
You have in mind a companion for sodastream and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sodastream in all years. Click on graph for more.
sodastream
soda siphon
seltzer bottle