I am actually reviewing the Argos Review system not the store itself.
There are several problems with it:
1. You have to be invited to leave a review.
2. When you are invited to leave a review it is done by email shortly after your purchase and therefore probably before you have had any problems with the purchase. It is not possible to update these reviews later on.
3. If you simply pop into a store and purchase an item there is no way to leave a review
4. Argos vets all reviews before publishing those it finds acceptable.
Keeping the above in mind I now pay very little attention to Argos reviews