Anyone out there beat mass effect on insanity? Cause God dammit its been 3 fucken hrs that i've been stuck on horizon!!!
Im playing as vanguard , was that class a bad choice? if so i dont mind restarting over if its easier with a different class. 
Oh and if i import my level30 from my first playthrough can i still get the achivement? I remember that in the first it wasn't allowed, you had to start from scratch. 
Any help is appreciated if not i'm going to quit i don't want to build up any hatred against this awesome game!!

I currently got to Illium, Insanity is my last achievement. 
 
Imported a LVL 60 Solider from Mass Effect 1 / LVL 30 Solider from Mass Effect 2. Using AP Ammo instead of Warp Ammo, aka Tungsten Ammo, I haven't had too much trouble. 
 
I gotta say, going against those two Scions at the end of Horizon was...pretty ridiculous. I used the Collector particle beam to kill the husks, and then ran around the two Scions and prayed for dear life. But it's possible to get through.

Shoot the husks in the crotch/upper legs; headshots don't do it. That's about all i have for tips.

"Shoot the husks in the crotch/upper legs; headshots don't do it. That's about all i have for tips. "

I can't get past the first Collector's ship mission on hardcore, I hate it because I think I chose the wrong team to go in and we just keep getting hammered!

Just finished Insanity with a NG+ Vanguard (import at level 28). Didn't really have any problems on Horizon, but the biggest tip I can give is learn how and when to use Charge, if you've powered it up you'll get a full shield recharge every time you use it, and it only has a cool down of 3 seconds. 

Vanguard is not at all a bad choice once you learn how to actually use charge effectively (i.e. not as a means to bum rush)...I honestly thought it was the worst class of the six, but now having finished Insanity its probably one of the better classes

Edit: Also, advanced training ability was Warp Ammo (ranked to Heavy Warp Ammo). Don't bother much with Cryo Ammo, Pull, or Shockwave. I would max out Charge, Assualt Training or w/e its called, Incindiary Ammo (for armor) and your adv. training skill. 

It's definitely frustrating.  I played as Sentinel on NG+.

"I currently got to Illium, Insanity is my last achievement.   Imported a LVL 60 Solider from Mass Effect 1 / LVL 30 Solider from Mass Effect 2. Using AP Ammo instead of Warp Ammo, aka Tungsten Ammo, I haven't had too much trouble.   I gotta say, going against those two Scions at the end of Horizon was...pretty ridiculous. I used the Collector particle beam to kill the husks, and then ran around the two Scions and prayed for dear life. But it's possible to get through. "

Yes, I'm fairly certain you can get the Insanity achievement with a NG+ character. And you totally could get the Insanity achievement using a New Game+ character in Mass Effect 1. I went through that game with the same soldier three times.  
  
As for your problems on Horizon, I can't see Vanguards being that effective on Insanity. The whole point of Vanguards is go in guns blazing and then shotty raping anything and everything. While, in my opinion, Insanity is about taking it slow and steady. Anyway, because of the armor on the Husks and the Scions, I would bring Miranda, definitely. Miranda's Heavy Warp is REALLY good against armor. Also, Reave, Reave, REAVE. Reave is amazing against armor, health, and barrier.  As for your second squadmate, since you don't have Thane yet, I don't know. You can really bring anyone you want. Garrus'/Grunt's/Zaeed's Concussive Shot helps quite a bit against the barrier of the Praetorian.
 
Overall, I really think you would have a hard time with a Vanguard. I'm sure it's possible, and I give you mad props for going with that class on Insanity, however I would honestly recommend starting over with something like a Sentinel or Soldier. Maybe Infiltrator [Tactical Cloak, dawg]. Wait, no. Sentinels. I hear they're completely broken. As for me, I've gotten to Legion with a New Game+ Soldier, and it's been fairly straightforward for me. The only time I had MASSIVE amounts of  trouble is that first fight on the Collector Ship. And I can't even imagine going through that part with a Vanguard.
 @ptys: Thane and Miranda. Heavy Warp all the way against those fuckers! I was stuck on that spot with Garrus and Grunt for 5 hours when I finally realized Miranda and Thane were the way to go.

@h83r: Actually, Horizon is a prime example of where Vanguard works well, especially in the defend the controls for the turrets portion, because theres enough cover that you can charge nearby enemies for a free shield recharge and either A) get back to cover or B) be right in their face with a shotgun and kill them in a 3-4 shots tops. 

Also you can basically run circles around Scions with a shotgun and abuse the charge for shield recharges. Seriously, on the retrieve IFF and final mission I took down every group of two Scions without help of dead teammates by running circles around them, getting close enough to trigger their discharge, but backing out of range.

Edit: Also, Miranda is always a good choice for her boosts to squad health and weapon damage