outstanding support

Best WHMCS integration plugin, period.

You’ll have to do your homework and test out how this plugin does the integration before going live. May require some customization not only on the WordPress side but to the WHMCS template as well. Hint: don’t be afraid to put on your developer hat and fully tinker with the templates… PHP, HTML/CSS, jQuery, AJAX, JavaScript and all. It isn’t going to work right if you don’t put the effort to polish it.

Once it is all good, or close to what you want, go buy a PRO license to tie it off. All this is worth it to have one seamlessly integrated front end.

Oh and tech support is superb. They only answer tickets from M-F 9-5 CET (Central EUROPEAN Time), but they sure get things done. They were able to turn around a fix for a performance issue I found in less than 8 hours!