Jumping back in-server questions

It’s been a long time but I’ve ordered a new laptop to get back into LOTRO. Played from 08 thru Riders of Rohan. I played on Vilya I believe back in the day. It appears only the most popular servers are left from back in the day. Had a question regarding the legacy servers or maybe they’re called legendary? Apparently they’re VIP only. What gives on those? How are they different from say Arkenstone for instance?