This is a fantastic question! In my experience, for competitive research/marketing, it is critical to spend time with your customers and frontline sales teams. In my previous roles, I've built voice of customer programs to help support quant and qual research. This has come in a number of formats - a win/loss VoC program for enterprise sales deals, an annual customer survey and a churn surey. I've typically used survey tools like Medallia, Qualtrics and Gainsight. The key is being able to build a repository of these insights and operationalize them across the organization so people take action from the customer feedback.
Typically, when I've done win/loss surveys, I will send a short survey to the customer (think 3 questions max) with one question asking if it is okay for a 30 minute phone follow up. I'll typically do a more in-depth interview where I can go in to specific questions about product, marketing, sales process and of course, competitors.
I think the best VoC programs are the ones that operationalize across an organization. Withr egards to messaging, I've typically used those findings to do messaging audits once a quarter. The other area I've focused on with customer feedback is helping inform our product roadmap strategy and general GTM strategy (I.e. identifying the white space in our messaging, product investment and amplifying our differentiation).