Hi guys, I too played AO for over 2 years, upto the point of Alien Invasion coming out, I was Omni through and through all that time, My toons made it as far as Penumbra in Shadowlands, but I never bought AI. AO was going through a tough time then and was losing a lot of players, my Org fell apart as most had been playing longer than me and had become a little bored. My own personal experiences on Rimor are as follows:
Far more clan than omni (most people like to play rebel chrs), Overall I found the Omni side a more mature set to group with (though I didn't go outside of the Org much I have to add, and this was my pre-TOG days).
The raiding as I understand it on Atlantean you had to be a member of one of the controlling Orgs to get a chance to be in on it. On Rimor some kind people set up Raid bots which you registered with and they then notify you in chat when a raid was to start, e.g. Mercbot.
When they released Shadowlands the economy went out of control through the dropping of ingots from hecklers (which also gave the best exp per kill) I'm not sure if that has balanced out now.
I would think carefully about going the Neutral route as for SL this has serious implications (if I remember correctly) some content you can only go through if you aligned Omni or Clan.
I'll see if I can find all my old links and post em for you.
Sadly I stripped all my old toons for my last few friends in the game otherwise I had a hell of a lot to give
Yipchun - Ex Omni Martial Artist