Create a view to show nodes tagged with certain terms next to each other in comparison table
The way I would implement this in Views is to create a node (of type 'Products Feeds') for each product the way you suggest.  Then I would add an additional field (field_unique_product_code) and make that field a taxonomy term (term reference) of a vocabulary named 'products'.  That vocabulary would contain unique products codes for all the products your system will process.  The shops need to use the same unique product code (or you need to translate shop-specific SKUs in the incoming products feeds to this unique product before saving the node).  Note that while the product codes may be strings (e.g. sony-kdl-46R473a, each term gets an unique numeric id in the vocabulary (for instance, the term for this particular Sony tv model may have the numeric id '42'.  Take a note of this number, because you're going to need it later.

Now, perform the following steps:


Create and save a new View named 'Comparisons' and make it a view of type 'Products Feeds'. Press 'Save &amp; exit' to save and exit.
Go back and edit the View:


Make the format for the View 'Grid'.
Click on Show: Content, and change the radio button from 'Content' to 'Fields'.
Add the fields you want to display (shop name, price, description), rearrange the sequence and remove the display of labels.



If you look at the auto preview (bottom of page) at this point, you'll see that you have a nice grid display of the shop name, price and description, but for all the products, rather than for a single product.

To narrow down the display for a single product, you need to add a contextual filter.


Expand the Advanced section (to the right in the Views UI), click on 'Add' next to  Contextual Filters, and add the field_unique_product_code as a contextual filter.


Now, look up the numeric ids for your unique product codes. Let's say your database contains a product with product id 42.  Type in '42' in the textfield with label 'Preview with contextual filters', and click 'Update preview'.

Now, the preview should be restricted to a comparison between the shops, restricted to a single product.  Click 'Save' (top right) to save the View.

Now, you can produce comparions of specific products just by including their numeric product ids in the URL.  For instance:

http://example.com/comparison/42


will produce the comparison grid for the product with numeric product id 42.

This should give you the basic functionality you're looking for.  A lot of refinement is possible.  For instance, if you want to use products names in the URL for contextual filtering, you need to create URL aliases for the numeric ids (you do this with Administration » Configuration » Search and metadata » URL aliases).

For more refinement, you can use templates to get a nicer layout of the table grid, and add a left column with labels.

(But if you need help with these refinements, ask separate questions after you've got the basic grid with the contextual filter working.)