Even when you find a good review, there are complexities of manufacturing (and some intentional obfuscation) that make it hard to compare products or know that you are buying the exact same thing that was reviewed.
If you buy the same item a year after the review, it may have changed. This could change performance but be something totally innocent, like the factory changing suppliers for a key component.
Another pattern is this: Large retailers buying in volume are able to customize what they buy, so the "same" product can differ depending on where you buy it. Differences can range from harmless things like "exclusive" colors all the up to changes in functionality, cheaper internal components, and so on. Sometimes the model numbers are not changed.
Another approach manufacturers use is to use slightly different model numbers everywhere which makes it hard to make exact comparisons. This is common with mattresses and appliances.
If you buy the same item a year after the review, it may have changed. This could change performance but be something totally innocent, like the factory changing suppliers for a key component.
Another pattern is this: Large retailers buying in volume are able to customize what they buy, so the "same" product can differ depending on where you buy it. Differences can range from harmless things like "exclusive" colors all the up to changes in functionality, cheaper internal components, and so on. Sometimes the model numbers are not changed.
Another approach manufacturers use is to use slightly different model numbers everywhere which makes it hard to make exact comparisons. This is common with mattresses and appliances.