In the absence of any specified requirements, the presence of 512 RAM along with burst-table RAM of 1 GB meets the standard requirement in good vps hosting plan. It is quite possible that the VPS hosted plan itself is offering choice of control panel among many available options, which usually include Plesk or WHM/cPanel. In their respective functions these cPanels are having great similarity in their features. The user friendly cPanel is responsible in making the tasks very simple in their applications in respect of adding domains, debugging besides setting up email accounts.
In case a VPS provider offers only limited plans, is not worth considering for going ahead with the plans offered. Therefore before finally deciding on a VPS plan, one should ensure that there is possibility of affecting needs based customization.
In case there is necessity of 500 MB disk space besides 5 GB monthly data transfer and 512 MB of fixed RAM, it is totally irrelevant to make choice of a VPS plan offering 80 GB disk space, 1000 GB of per month data transfer and providing 512 MB of fixed RAM in the plan.