I'm not really the best person to to get solid answers from, but for me, a multiplayer n00b, I find HQ very likeable. In early game I barely touch the tanks other than Shadow Tank and Gatlings (and little bit of Stingers just in case) so I usually go Pandora first before radar. Stalker is nice siege unit, and if you're rich and sneaky enough, you can pop them right at the back of the enemy base with Driller. Somewhat good support with Brutes.
Colossus is quite a necessity too if you want to survive tier 3, Shadow Tank is good if you want to ambush enemies in guerilla tactics all day or want to kill infantries (their range is impressive too), but Colossus holds the real firepower if you want to duke out against tanks or air. Just don't fire too close to allies tanks. It has tendency of friendly fire in danger close situations.
Rahn is fun hero to play with especially against infantry spam, and his range means that he usually shoots first (insert Star Wars meme here) when it comes to Hero duel, or he survives long enough to land his shot. Heroes with range like Morales and Siegfried of course beat him in this case so that's no debate but one can argue that he can beat Fin.
Now Irkalla, I'd say that if you have no escort, just keep it in your base. Heavy air assault and mass of units like Archers and GGIs spam beat it quickly. Otherwise it's 3k cash gone to the drain. It's still a good area denial, but you really don't want it alone.
As for support powers, I like Geneburst as harrassment and thinning infantries. Barrier is great, with no cash cost to increase survivability of your infantries. I once used this on my Shadow Ring Dune Rider for assured destruction. As you may already know, it's not effective against Terror Drones
This is all opinion and others can probably say better than me
Edited by Handepsilon, 10 August 2017 - 02:11 AM.