Dual Vinyl or Dual Aluminum
Yes, there is a difference!
Because buying the cheaper, wrong window is always more expensive that buying the right one the first time, I would move you away from the windows from the "big box" stores.
I would look at some of your local dealers and then I would ask everyone I knew what they have and how they like them.
Aluminum windows that do not have a thermal brake, can cause heat loss.
Vinyl windows that are not re-enforced over certain widths can sag.
Vinyl windows that have welded sashes should be fine if the glass is attached to the sash all the way around.
Aluminum frames only offer one advantage, you don't have to paint them.
The simple answer is (In most cases)Vinyl is much more efficient then aluminum.
If you buy a good Vinyl window you will be happy, However be aware of big box stores like Home Depot, ******* and ***** . These stores have their place, they have self-named themself's Home Improvement Center's.
These are Discount Do-It-Yourself stores.
They are a great place to but paint, Beef Jerky, work gloves, Christmas Lights, etc.
Ask yourself this question.
Would you buy a home that was built with materials form a big box store?