Two great myths:
Titanium is lighter than aluminum
Aluminum boils faster

Titanium is heavier than aluminum but stronger, hence the walls are usually thinner so the pots are lighter. For a boil only use, because the walls are thinner they will heat up your water at about the same rate as a similar sized/shaped aluminum pot.
Keep in mind that a wider pot is usually more efficient than a taller one. IE 500ml will boil about 20% faster inside a 13cm wide pot than a 8cm mug even using a narrow flame.
Franco