phaolo: Round Attack seemed only good vs weak or wounded units, though.
Round Attack is always good. Not only can you hit multiple units in one go, but it does not allow for retaliation.
So, if your hero is fighting something tough like, say, a Syron, and you both attack normally, then every turn you'll attack 4 times and the Syron attacks 4 times. (2 normal attacks, 2 retaliations each.)
But if you use round attack, then you get to attack 3 times, and the Syron only gets to attack 2 times. (You get 2 retaliations and 1 round attack, he just gets his 2 normal attacks.) So you attack 50% more often than he, and stand a much better chance of winning.
If you have extra strike, you'll attack 5 times and he'll attack 4 times. Still an advantage, but you'll only 25% more often. (Extra strike only works on your own turn.) So Round Attack is usually the best option.
And it becomes even better when you have some disabling or debuffing ability, like Lightning Strike or Death Strike or something. (From a magic weapon or spell, or when you select it on character creation. Can't pick those on level-up, unfortunately.) Then you can debuff 2 or 3 enemies in one go.
At only 5 points round attack is a steal.
The only time not to use it is when you'll hit your own guys, when you REALLY need to kill something this turn and not later, or when facing missile troops. When you're attacking that ballista that won't retaliate and needs to die right now, Extra Strike really comes into its own.
I often used EW, but somehow I didn't get that it gave me Magic Strike -_-
First Strike still seems good, however..
Oh, yes. First Strike is amazing. That halberd is definitely something to keep.