still not sure as no idea how secure their certs really are.
CPanel already has a buy SSL cert option in WHM, but I have this disabled as it is a rubbish SSL and will only cover either www or non-www whichever you chose, but will not cover both options.
These certificates will hold as many domains/subdomains as you want, but you can only request 20 (or an additional 20) in a single API call.
It's doubtful that a single account will have more than 20 domains.
As for security, any SSL certificate generated with the same number of bits is as secure, even self-signed, but they do seem to be trusted by all of the browsers.
Many CDNs use them Akamai, CDN77.com (which makes sense) and all the enterprises listed on their website.