Brian,
For my two cents worth, I think that the forum SHOULD be updated, but stick with the VB platform. I feel that it is the only one that can virtually guarantee the archive is solid. As you and other members have pointed out. the archive is where much of the value of the site is garnered. With the information on their website, it look like the learning curve would be minimal. and the V6 portal looks very familiar to other Christmas hobby sites. (I could not find where the V5 is even a reasonably purchasable option - the cheapest licensing I found was $249)(
https://www.vbulletin.com/en/checkout/cart/configure/id/21769073/product_id/28/)
It looks like the primary goal of xenforo is monetization. the paywall does not seem to permit non-paying member access to much if anything other than perhaps viewing the site - non-participation.
"User upgrades
# User upgrades are one of the monetization options included in XenForo. This system allows your users to purchase increased access or access to additional features on your forum.
When a user purchases an upgrade, they will be added to one or more user groups. You would configure these groups to have additional permissions or provide access to additional areas of the forum.
Any content or feature, access to which can be controlled through permissions, can be attached to a user upgrade.
To setup a user upgrade, you must first setup a payment profile via
Setup > Payment profiles. These profiles define how the payment will be processed and received. Once a payment profile is defined, the user upgrade can be configured, including options surrounding cost, duration, and whether the upgrade is automatically extended.
Users can purchase upgrades from the
Account upgrades page listed under the account menu."(
https://xenforo.com/docs/xf2/user-upgrades/)
it just does not seem very "friendly" to the lighting community as a whole (IMHO). it seems that there have been several issues with user migration (seen in the white pages) from other forum platforms. such as users being frozen, locked out, omitted, deleted, or even combined with other users.
Vbulletin 6 is $179 compared to Xenforo is $160 (both are for the self hosting) - the cloud options seem to be way over priced (IMHO)
Im certainly not telling you or anyone what to do - merely making a suggestion and presenting what I could find on their respected websites (and others).
resources:
https://www.vbulletin.com/
https://www.vbulletin.com/en/checkout/cart/configure/id/21769073/product_id/28/
https://xenforo.com/purchase/#licenses
https://xenforo.com/docs/xf2/groups-permissions/#other-uses-for-groups
https://xenforo.com/docs/xf2/user-upgrades/