The best replacement for datastage is informatica.

The best alternatives to datastage are rated as following:
★★★★★  informatica
★★★★  ssis
★★★  ab initio
★★  odi
★★  pentaho
★★  talend
★★  ssis 2012
★  wtx
★  message broker
★  oracle data integrator
★  qualitystage
  data services
  datastage tx
  informatica etl
  powercenter

Your alternative for datastage is not listed? Suggest!
Speaking about datastage, one probably shouldn't forget about teradata.

Other search terms related to datastage and their ratings are:
★★★★★ teradata
★★ netezza
You have in mind a companion for datastage and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of datastage in all years. Click on graph for more.
datastage
informatica
ssis