We have successfully used Informatica Cloud to move data from production Salesforce instances to sandboxes. The trick is rebuilding the relationships between objects. If we use a config or dev only sandbox, we typically don't move all data from production, only certain components, such as active customers and data related to those active customers.

What I did was create a custom field, named Prod ID, on every object that we move and made it an external key field. I then populate this field using the Record ID of the same object when it gets moved from prod to the sandbox. For, example, I start with active Accounts and move those records from prod to sandbox and map the prod Account Record ID field to the Prod ID custom field that now exists on the Account object. For subsequent (related) objects, I use that field to associate other records to that object. The same works for objects that are 2 or 3 levels removed from the Account object. As long as you move them in order and have the Prod ID field populated, you can rebuild the relationships when the data is moved from prod to sandbox.

If you want to chat more, please send me a direct message with your email address and we can set up a conference call and/or demo of how we do this.