I can't remember ever being stuck over an hour at a single encounter in Reach.
The pylon sequence was ridiculous. Taking out banshees is nigh-impossible with the provided weapons (light rifle, supressor, boltshot, storm rifle, needler), and taking them down with a plasma pistol means you have to let them come at you (and they will obviously fire at you) before firing at last second, which results in around 1/3 or 1/2 of your shields being drained. I can't tell you how many times an elite finished me off with a carbine while I tried to do this.
And I can't take out that elite because he is standing on top of the pylon and will retreat into the structure if I fire at him.
Even if I manage to PP the banshee, it mostly lands on the other side of some structure, and by the time I get there, it's airborne again.
Fuck yes that encounter was unfair as hell. Straight out of CoD4 grenade spam hell in terms of unfairness.
Funny thing with the huge gun in reach is you don't actually have to use it, you can just wait around until he says "FIRE IT NOW" and run up and do it.
that's what i did for my legendary solo run at least