I still think it should be at the very top. Generally in marketing you put the biggest benefit that has the broadest appeal as first in any list - so that you avoid the TLDR problem, and the most number of people perceive the highest benefit. If you know that 35% of people (in my case - who visit my web site by mobile) are going to be head over heals over this feature - then I’d put it way ahead of “conversations not pages” which really just sounds like marketing BS (and this is coming from a marketing person).
And, I think the benefit isn’t just “no app required” - but “Mobile Friendly” - or - “Read on your Smartphone or Tablet” or “Smartphone and Tablet Friendly”. Its semantics - but would put the emphasis on the inherent ability, rather than the lack of a requirement (to download an app).
Sure - android performance isn’t perfect - but its too easy in startups to focus on the negatives, rather than what you have accomplished. Its still light years ahead of PHPBB, or other such forum software.