How do you test and evaluate messaging of updated value prop in scrappy way?

There's very little I can say that someone like April Dunford hasn't said better and I find her approach relevant across b2b (where she developed it) and b2c. The following homework is required, in my experince, to generate a high-value positioning that can drive messaging, brand, and all gtm strategy, planning and execution:

• Hopefully, you've got some customers who really love your product and it's essential to understand what they think is so amazing about it. 

• Understand your true competition - if these customers didn't have you to solve their problem, who would they turn to?

• Perform an objective and very sober comparision between your product and those competitors. What is truly different and unique about your product? Think functionally here. We know how hard this can be and how much pressure there can be on us to exaggerate our differentiation. We must resist - the business needs us to be truth-tellers. 

• Play our role as translators and describe those functional/feature differences in terms of the benefits and value they provide customers. What's the point of our differentiation? What does it enable that nothing else can?

• Identify the segment(s) who will care about unlocking that value.

• Help that segment understand who you are by picking a frame of reference for the category you play in that makes conceptual sense to them. Here, it's really worth just picking up Obviously Awesome for the discussion strategic choices in picking marketing categories. 

In terms of alignment, the number one thing we can do is stop saying things like "product marketing owns positioning". This doesn't help anyone. Instead, make it a team sport. When you can help everyone in the business to be a truth-teller and get everyone sharing the same set of assumptions, you'll be amazed at how much of the usual back and forth between product/sales/marketing goes away. 

Make your key stakeholders accountable to the creation and success of positioning and listen their feedback after you launch. You're most likely going to change positioning frequently and look at each change as an opportunity to build better alignment.