Please note that if ADDLOCAL is not used then all available options are installed when installation takes place from the command line. However, if ADDLOCAL is used then only the components specified will be installed. Therefore, if PDF-XChange Editor was installed from the command line and does not subsequently display in web browsers, then it is possible that the browser plugins were not specified during installation. An adjusted reinstallation will confirm whether or not this is the cause of the issue.
A complete list of the MSI installation switches and their functions is available here.