I have plain ordinary aluminium windows in my home. Personally I love PVC - but I have aluminium and they are single glazed .
I believe that aluminium windows are a good product. The local ones vary a little depending on the manufacturer but are all similar in design. They are eminently suitable for their market. I have no qualms with: -
Southern Star
MTM
A&L
Stegbar
Rylock
Trend
Dowell
Their windows are all fine. I would have preferences but the difference really comes down to cost and service. I have personally recommended half of the list at any time depending on what I was asked by whom.
Hope this helps someone,
Ed