In case one of the places you didn't look was Jive-n 8 Upgrade Planning Guide, I wanted to call that out as having good information on upgrading to 8. With respect to the process, there are details in Jive Hosting Group.
If easier, I'd be happy to set up a call to talk through this with you. Let me know if that would help.
If you decide you would like to move from Jive 7 to the latest version of Jive 8, it would require a major upgrade. During a Major upgrade:
- A New set of Production and UAT instances are created to support the major upgrade.
- Once a mutually agreed upon time is determined and scheduled, the existing data and settings are transferred from your existing instance to the new instance.
To see more around the process, you can view this document: https://community.jivesoftware.com/docs/DOC-73529#jive_content_id_Major_Upgrade_Process
In regards to the difference between Hosted and cloud, there are a number of them but I will try to point out the major differences. With Hosted instances you can install modules so that you have access to certain features. An example could be, you install the Ideation plugin so that you can have the ability to create ideas and you install the Events plugin to be able to create Events. Whereas in cloud-n, there are three different tiers, Essentials, Essentials +, and Enterprise. The features you have are dependant on the tier you are on. This link will show you what is included in each tier: Cloud Versions
Another difference with Hosted sites is that you have to request to upgrade whereas with Cloud instances, Jive upgrades all cloud customers each quarter so that you are always on the latest available version.
In regards to what Jive 8 has to offer and what the latest cloud release (2015.2) offers, each of these blog posts go over new features for both:
Hope this helps.
Thank you so much!