I feel I got to share my recent experience using 'Disk Drill'.
Recently I accidentally formatted my external hard drive instead of my flash disc. I was devastated as my photographs for the last 9 years where also on it. After downloading several different programs I tried Disk Drill which I must add was the cheapest I could find. This program WORKS!!! I managed to get all of my information back including stuff which I have no idea was even there that was previously deleted (2Tb). The only issue, and not being major at that, is the original file names do not remain. This gives me a little work of going through each one to rename it but I couldn't be happier to have it back.
If any of you find yourself in a similar situation I would highly recommend using Disk Drill.
Hope you never feel the emotions I did at that time but if so, good luck.