You shouldn’t notice any difference and the link will never negatively impact the product. Plus the editorial line (the things we write) is NEVER impacted by these links. We aim to look at all available products. If it isn't possible to get an affiliate link for the top deal, it is still included in exactly the same way, just with a non-paying link. For more details, read How This Site Is Financed.
This is one area where going green and saving money diverge. The cheapest renewable tariffs tend to cost more than the cheapest standard tariffs, so it really is a question of your personal politics. However, if you can afford to go renewable, then it's a help to the environment, and all the main comparison services allow you to compare renewable tariffs.