Rather have my Little Giant ladders.

The first one I have is ideal, since it easily fits most anywhere, goes from a 4' to a 7' step in seconds, and is seriously stable.

The second one is a PIA, but is also one great ladder, other than the really heavy weight. It goes from 6' to 11' pretty easily.

Both can be extension ladders, but the large one can be a monster to set up or move around. Although I have used it many times in that extension mode, I would just as well have a normal extension ladder when going up high. But, again, it is the most stable ladder I have ever been on...