As a rule aluminum step ladders suck times infinity. Aluminum extension ladders do flex, which is annoying, but normal.
If you have a ranch style house, you really need a eighteen foot fiberglass extension ladder for getting up on the roof.
If you have a split level with a stairwell that is challenging for a regular step ladder, than get the Little Giant. If not, a good six foot fiberglass step ladder would be cheaper, lighter, and easier to store.
The ads always show the little giant used as an extension ladder, but that is not practical and is actually dangerous for someone not accustomed to using ladders. The "use it as two sections of scaffolding" suggestions are pretty lame after you have tried it once.
It excells in two areas.
Set up on uneven ground or stairs.
Used as a step ladder when you need to get up so far that you want to stand on top of the thing with one leg on each side of the ladder. It is very stable and you can stand on it higher than you can on an eight foot fiberglass step ladder.
The way I use my ladder, I would not trust a cheap knock off. I trust my life to the Little Giant several times a year, putting me into spots where a sudden fall would be disaster.