Timothy Pearson wrote:
LetsEncrypt does not appear to be secure enough as it effectively requires automated certificate installation on the master servers, and furthermore I expect it to be removed from as a fully trusted root CA or at least demoted in some way in the future [3].
I'd suggest a little more research while paying attention to the originating source material (CA's who are losing money). At least one of the FUD sources in your link has been responded to: https://unmitigatedrisk.com/?p=552.