It's tick based, it requires alliances, and moves should usually be thought out. Ultimately, it requires only a few minutes to play, and is free unless you pay (yes, IIUC, paying once locks out the account from ever being free again). It $15/yr that most certainly is not needed right away, and the credits that it gives you can be bought in game anyway.
It's probably worth checking out, it really takes a only a few minutes, unless you're interested. SC2 is mature, SC3 just opened (can only be in one Star Cluster at a time) so there should be room for everyone.
Oh my, did i just advertise? Somebody slap me.