There is no Plus plan, that is something specific to your host. AFAIK you cant upgrade to a Cloudflare plan as long as it is provided through your host.
Generally speaking though, Cloudflare’s default certificates support the naked domain and a wildcard on the immediate next level, but nothing of the sort of www.what.ever.com.
Does the Cloudflare SSL cert also include multiple subdomains, site seals, 256 bit encryption, mobile/browser compatibility? Would love a features list if there is one.
Re the PlusPlan yes, that comes via SiteGround (attached image) and Cloudflare blog post suggests upgrading to Pro Plan if we have SSL cert for our site.
That is something your host is selling and not part of Cloudflare.
As for the hosts (“subdomains”), I already addressed that. Site seals are meaningless. The encryption bit might come down to the cipher. The Cloudflare certificates are generally well supported.
From what I can tell it would seem as if your plan included SSL anyhow.
That post is from 2012 and I believe that information is outdated. I have the Free Plans directly on Cloudflare on sites hosted by Siteground with Let’s Encrypt SSL and all works fine. Cloudflare provides free SSL at the edge (their datacenters), while Siteground offers free Let’s Encrypt SSL at the origin, allowing you to benefit from a Full (Strict) setup. You’d only need to pay for a Cloudflare SSL if you have more than one level of subdomains (subdomain.subdomain.example.com), but nof if you have multiple subdomains (www.example.com, test.example.com, m.example.com etc)
Both the Free and the Plus alternatives available through Siteground include Railgun, which you will not be able to implement if you have a direct account with Cloudflare (even a Pro Plan or higher), as Siteground AFAIK will not support Railgun except for users of their own Cloudflare plans.
What you can do is grab a $1 domain, install it on Siteground and place it under a direct account with a Free Plan on Cloudflare, and compare speed improvements.