The upgrade fee that Jelsoft charges is for 1 year of upgrades not per upgrade. Plus it is not required that you upgrade to every new version. We will let you know if a security risk is found and then you can choose to upgrade or download a patch.
Our installation process is quite simple and we have step by step instructions on how to do it in our 500+ page Manual. These instructions include screenshots in order to provide more guidance. If you know how to turn on your computer and use a web browser, you can install vBulletin.
The add-on portals are third party software so we cannot support them but the vBAdvanced installation is quite easy and they provide an excellent support community of their own.
As for converting from your existing software. We provide excellent one-on-one support and guidance for you to complete this process. We did offer it as a service but a majority of our customers complained about it so we made downloadable scripts for it.