Proprietary versus Open source ETL tools

[Tommy Rs]

Hi,

As of today, we are still enjoying our Informatica tool but in a few months we will need to change. Basically we do not use our software at its full capacity and don't feel we need it anymore.
So we are trying to find a less expensive solution that would have the same features (or almost...).

We are looking at less expensive tools and Open source software. We have pretty much targeted a few companies and would like to know which ones would be the better solution compared to Informatica.

-Apatar
-Expressor
-Pentaho
-Talend

Some are paying software, some are open source (but not free...), so i'm asking you to know which is the best software on the market.

Thanks.