I've been re-working the landing pages for a few of my products recently and while the landing page course by Unbounce is amazing, I've found it really hard to get educated feedback. I generally end up turning to Reddit's /r/entrepreneur, or the various startup slack groups that I'm in to get some feedback, but it can be a bit hit and miss. Then, just yesterday I saw @tommedwin posting on Reddit about his experience with the Best Morning Ever, and how he used The Pit to get actionable feedback on his landing page. I know in its current configuration that it's not really 'productised' per se, but 99Designs started as a sub-forum on SitePoint and I think this is pretty comparable. Definitely a great resource for anyone who's looking to improve their landing page.