Many ranges from every company. They all have diffrent spec in each range. How you know you are comparing the same range? If compare lower end range model from company A to a higher range model from company B, then not valid.
A method might be to use the price, but then make sure the prices are "fair" as for mattress, their "discount" purportion are very wide (from those 90% banners you see all the time).
To add to the confusion, many furniture retailers with a large enough chain "rebatch" particular models. They still maintain the original brand but the model name has changed.