Recover deleted trash files on Mac

Long story short: 2am, very tired, in a hurry, deleted all docs from wrong device, emptied trash.

I've been asked to recover files for someone who has mistakenly deleted all documents on their Macbook. They were attempting to clean up a usb device in preparation for backing up the macbook documents to the usb device and, well, bad things happened.

On Windows I've used GetDataBack for NTFS & FAT many times for this kind recovery option. Is there anything similar for Macs? I don't trust the sites that switch domain names when you move from*"hey this software works!" pages to the download and/or purchase pages and that just looks too sketchy to me. So please just talk about software you have personal experience with. I don't have the computer with me yet. I'm trying to find out what I can learn and prepare for before I get started. To aid in the recovery effort, if needed, I have access to Windows 7 machines, an iMac and USB HD-SATA and laptop HD adapters.

The best software for data recovery is called "Data Rescue 3" from Prosoft. It's not inexpensive though so I suggest downloading their trial version first. I can testify to its use since I own a copy.

First , the best one can do is shut down your Mac and not use it any longer. Hold down T when turning power on and boot up in target disk mode so that the drive is accessed as an external drive. You should run the recovery from another computer.

I successfully was able to recover lost files using Disk Drill, but each use case is different.
In any case, the longer you use the Mac, the less likely it is to recover any data.