The best value proposition is clear: what is it, for whom and how is it useful? If those questions are answered, you're on the right path. Always strive for clarity first.

If your value proposition makes people go "hmph?", you're doing it wrong. If they have to read a lot of text to understand your offering, you're doing it wrong. Yes, sufficient amount of information is crucial for conversions, but you need to draw them in with a clear, compelling value proposition first.

Research by MarketingExperiments says that the key challenge companies have is identifying an effective value proposition, followed by communicating it clearly.

What makes a good value proposition:

• Clarity! It's easy to understand.
• It communicates the concrete results a customer will get from purchasing and using your products and/or services.
• It says how it's different or better than the competitor's offer.
• It avoids hype (like 'never seen before amazing miracle product'), superlatives ('best') and business jargon ('value-added interactions').
• It can be read and understood in about 5 seconds.

Also, in most cases there is a difference between the value proposition for your company and your product. You must address both.

Here's a value proposition worksheet you might find useful.