How to delete a node with same specific field content and by same user when a more recent one is created in drupal 7?
Here is how I achieved it in the end:

First, create a component rule 'Listreviews'. This component rule will filter nodes created by the current user and then 


Component plug-in is set to 'rule'.
The variable is of type 'node' of type 'parameter'. Give it a machine name 'nodefromlist' and save.
Add a condition: data comparison. This comparison will be have the data selector nodefromlist:author:uid, and it needs to equal site:current-user:uid.
Add an action: 'delete entity', which will have the data selector value of 'nodefromlist'.
Save!  


Then, create a rule 'Delete duplicate review'.


the event chosen is 'before saving content type review'  
no conditions  
Actions: 'fetch entity by property'

entity type 'node'  
property: the field 'location' (in my example)  
data selector: go down the arborescence up to: node:field-location  
I put a limit of 10, but may need to be adjusted based on previous content available.  
Add a label to the provided variables section  
Add a variable name like: item_same_location  



Then


Create a loop below the action above with the parameter item_same_location  


call the current list item: list_item.

In that loop, create an action 'component' with the name of the rule component created above.


the data selector will be: list_item.

Save your rule!


This should now work. As a bonus, I added a 'display message' action in the component rule in order to let the user know that their previous review was deleted. I hope this helps someone in the future!