Aluminum ladders work fine if you buy the correct class of ladder. Most of the ladders you see for sale at hardware stores are grade 3 and for light duty home use. If you want a ladder that doesn’t bend or wiggle, buy a higher-class ladder. Get a grade 1 ladder if you don't like falling.
Fiberglass ladders are light, sturdy, non-conductive, but quite expensive.
Wood extension ladders are great if you can find them. Around here they are quite popular. They use aluminum rungs to keep the weight down. They're non-conductive, sturdier than aluminum, same weight as fiberglass and about half the price.
Here's a site of a local ladder maker.