I've read a lot of praise from various reviews regarding this games. I just need to confirm something though:

Is the AI like Company of Heroes' AI? No turfing allowed?

Curious because in CoH a panzer can attack you while you're still building your own mech shop. Is the AI in this game pretty much the same? Because if it does, then it'll be pretty entertaining.

Mammoths missiles aren't worth noting at all. They fire 4 once every 15 seconds or something. pitbulls die too easily, so the only real option I found was APC's with a missile squad in it. The APC itself already is a AA and with the missile squad they're even better. I only used Firehawks later on against the big scrin ships.

Nod is a lot easier. Their AA defense is a lot better, they have stealth tanks, venoms and attack bikes.

My favorite mission no doubt was the GDI mission where you had a base with limited power and you had to manage your base defenses by switching them on and off. The AI spammed a lot of vehicles from the NE base, Infantery from the SW base and Aircraft from the SE base. It was awesome.

God that was a pain in the ass to finish, finally managed it the other night though, on about my sixth run through.

I'm liking it though, I just think that there isn't enough variation between the skirmish maps, they all seem to look the same to me, and the music, it sucks big time.

Mammoth rockets ALWAYS existed so the thing isnt completely helpless against aircraft, but they never had any real practical value (except in Red Alert where they had homing properties, mauled infantry, and rate of fire was same as main cannon).
APCs are basically Battle Fortress Lite, so they are the best anti-anything as far as defense goes.

Also it's funny that you can still mass build the same units and wipe out cpu bases in one go:
GDI - Mammoths with railgun
NOD - Venoms with lasers (like 50+ of them, they are super cheap)
Scrin - mass airforce with forcefields

hah...battle fortress, yeah they're always was always risky to use them though with those cheap yuri mind control units, so I usually put in a few seals to nuke all infantery, that's at least yuri clones out of the picture. Overlords from generals had a bunker you could put on there and put 5 missile guys in there, but I usually put on gattling guns instead.

And yes, venoms ftw. 50 of them, and it's you win.

Man, does anybody know how to beat Brutal GDI in Skirmish? It throws multiple dozens of tanks at me by the time i have one Mammoth. And after that, its literally a constant barrage of tanks and rocket soldiers, without stop. Well, constant up to the point where he sends Juggernauts and Mammoths at me cause thats when I die.

3 on 3 skirmish with AI opponents and allies, all set to balanced.
Turtlers are actually easy to beat, as long as you can nix their superweapons (kamikaze airforce works for that).

Whenever I tried that, by the time I had a few scorpions or predators, he had 12 juggernauts. The only thing I found that worked, is make base defenses, shitloads of them, until you had your own force ready. Brutals just rush too good and too fast to otherwise stand a chance, especially GDI.

OK other question then. Does anybody else had their Harvesters stuck? As in, not moving, not harvesting, doing nothing even when I tell them to. This often happens on bigger matches (3on3, 4on4), and most often with the NOD and Scrin harvesters.

The harvesters stop harvesting when you need more silos, but I don't think that's what you mean. I don't think I had that.

I did however quite often have a war factory screw up, and the result was EVERY single unit that came out of it, got "stuck" and just couldn't do shit. Even after you sell the factory they still won't budge.

The one where they were all stuck in ONE place? I got that once, with about 6 mammoths. At the very least, they made heckofa powerful stationary defense (before they got nuked).

Well that's what I thought as well, but they wouldn't even shoot properly, like there was a invisible wall around them. It wasnt mammoths though, predators, but still it's a stupid bug.

Having finally got to fool around with this at the local Virgin, I'll agree with you, this is a fun mission. There's a rather interesting strategy I ran across on GameFAQs which makes it even more fun; here is one of several threads on the matter.

Yeah, I'm not surprised a lot have trouble with it. 2 of my friends were stuck at that part for ages. I had a blast with it. I didn't get the MCV until I destroyed 2 of the NOD bases. Taking over the NE base makes a huge difference.