I REALLY enjoyed the first level of reckoning, my first time playing it all I could think was "holy shit this game mode is so -blam!-ing fun and cool" I had just gotten Thorn and was just running through it having a blast. Then I played tier 2 and realized how annoying it can be, I haven't even tried tier 3 yet, but if it's worse than 2 I can see why you would have some complaints.
3rd part is o.k. but you need people who know what they are doing, else it is a painful burden.
That first area is the fun part, then the bridge mostly sucks because it's either you complete it, or you get cheesed and get thrown off the side and timer runs out, then the bosses are... mehhhh. Using code of the commander titan with ursa furiosa against the two hive sword bosses to protect my team was fun for a while, but then along comes blackout to ruin everything