Hi Nurhaisyam
The benefits of subscribing to Totara are outlined on http://totaralms.com/services/subscription-options and include the upgrade and support of Totara through the support portal and wider community.
Totara has a flexible architecture - what is required is a web server that runs PHP this could be Apache or IIS and a database (MySQL, POSTGRES, ORACLE and MSSQL)
If you are already using Moodle then you will know the benefits such as easily customisable, very widely used, low cost, and the open source development model enabling fast and secure development of additional features. The additional benefits for Totara are the support and additional features for corporate Human resource planning.
There is some more detailed information on competencies at
http://www.kineo.com/moodle-insights/totara-feature-close-up-competency-frameworks.html
I hope this helps.
Craig