I started with the Onyx 300 pt box, so I'm a little biased, but my thoughts on the "starting with a sectorial vs. vanilla" debate is that it's a lot easier to plan purchases around a sectorial. CA has quite a few different playstyles up it's sleeves, but much of that is due to the different sectorials offering very different approaches to the game (they were mentioned upthread, so I won't repeat them here). Sticking to one, then, might make it a bit easier to list-build as well. The absolute best way to get into the game is through one of the two-player battle boxes, but that requires you to (a) want the sectorial in the box and (b) have a friend that wants the other half of it. The soon-to-be-released Operation: Wildfire is the only one with CA units (Shasvastii), but from a couple of your previous replies, that might be the sectorial of choice for you anyway (lots of misdirection and one hell of a centerpiece in Sheskiin). That said, that box and one other unit are the only updated models for the sectorial so far, so you might need to wait on the release train for a while to fill it out. Last thing to note: CB has an incredibly lax proxy policy. Basically, as long as it's the same silhouette value, it's fair game (and I mean, in tournaments!). Don't go overboard, but if you end up getting some basic troopers only, you can proxy them as other things to see what they do. The only "essentials" then for any CA player no matter their sectorial of choice are the drone box (or two!), a couple Imetron/Ikadron blisters, and the Obsidon Mechanoid (lovingly called "Doc Worm" around these parts). After that, it REALLY depends on your playstyle.