Good morning forum, so, after months and after completing three armies (PanO and all its sectorial, Hassassin and Phalanx), now I'd like to have something new, my main candidates are the ones I wrote in the title, YJ seems the most interesting, despite the recent news (lost JSA), Nomads have always a great charm but I played CA in the past and their new miniatures, Avatar & Charontid above all, intrigue me. So, some advice?
Go for a faction that plays the most differently to your present armies, and then add to the faction over time. I'd also start with sectorial and then expand. Onyx, IS or CjC are a good and safe starting points.
I would say go Nomads as they offer the most varied style of play. Those cool models you mention that intrigue you are all very good but you will seldom see more than one of them in any given game, as they're quite expensive and pull one from the other in terms of space and order feed.
I played Nomads and YJ recently 'cause I've a base of both, personally I like more YJ playstile 'cause is a sort of bridge between PanO & Nomads, they've powerful BS units and some tricks and melee but you right, the rebels have really a varied style of play and with their peculiar gameplay every match is different and my opponents are often in trouble. It's really hard, considering that, I hope, very soon we'll see Invincible army and subsequently Tunguska.
Go onyx. You can make a surprising amount of variety, even with small 10 order lists, which are also easy to paint up. Of course that means no charontid or avatar, so dunno how you feel about that. :(
I played Onyx several times before leaving CA, it's not a bad army but I prefer vanilla just 'cause I've Charontid, Avatar, the Anathe and more variety and flexibility. CJC is interesting, is the only Nomads sectorial I like, It's certainly an option I'm considering.
