S/MIME Certificates

I am seeking a quality provider of S/MIME certificates for email authentication and encryption. I tried Secure Trust for an S/MIME certificate but could not get it to install in either IE 11 or Firefox browsers. due to errors. They also have terrible customer service. I use Google Chrome browser so a S/MIME cert that will employ Chrome would be ideal. It appears that their many certificate suppliers??? Amy suggestions would be appreciated.