It is the best in that you will have the maximum amount of feedback/suggestions/critics. It helps you discuss with your potential users and helps you refine your ideas. It's one aspect people critically need at the beginning. It's one aspect people do not have with the anything that uses ads on internet (landscape+ads to see if some facets of your idea are successful, or prototype+ads).
It is the best in that you will have the maximum amount of feedback/suggestions/critics.
I can't imagine that's true. In a couple of hours I reckon you could talk to maybe 20 people in a busy Starbucks. Spending a couple of hours writing a great Show HN or Producthunt post could get you more feedback from a wider audience without costing you $20.
It helps you discuss with your potential users and helps you refine your ideas. It's one aspect people critically need at the beginning.
Strangers in a coffee shop aren't "potential users", even if they think they are (nor are HN readers for that matter). Any randomly selected group is effectively useless for gathering data - there's too much noise and not enough signal.
If you want good feedback you need to approach people you know are actual potential customers. You can't rely on luck. Go to places where they gather - user groups, meet ups, websites, etc.
