The Chamber Court in Berlin has ruled that phrases such as “sell at the best price”, “sell at the best price”, “Quickly and at the best price sell your property”, “Best price achieved in 92” and “The best price for your property” are misleading and thus according to Section 5 Abs. 1 sentence 1 and 2 no. 1 UWG are unfair.
In particular, a commercial act is misleading if it contains untrue information or other information capable of deception about the benefits of a service. Those conditions would be met in the case of such statements, since there was an untrue claim of excellence.
The court also delimits allegedly similar statements:
However, the meaning also depends on which reference word a connection is made with. For example, when a feature of a thing that depends on subjective criteria (e.g. “best location”, “best view”, “best wines” is referred to), it is clear that the real superlative cannot be meant. The corresponding assessment of the location of a property, the view from a hotel room or the quality of a wine depends on so many subjective and relative criteria that an objectively best cannot be determined at all. In that that way, there is no statement that can be verified in terms of content. […] If, on the other hand, a measurable size such as the price is referred to, the real superlative is generally meant. This is because there is a verifiable statement here. For example, you can determine whether a particular product can be purchased more cheaply from another seller at a given time.
The use of the particular article would also speak for the importance in the sense of the real superlative.
When used without a specific item, a mere indication of a very good quality is closer (“best selection”), while its use (“best selection”) is closer to a unique selling point. After that, for example, an advertisement with a sale at “best prices” would only be an indication of particularly high prices. On the other hand, advertising with the phrases “The best price for your property” and “Quickly and at the best price to sell your property” is a top-notch claim.
The creation of one’s own advertising or design of one’s own website can therefore be quite linguistically defizil.