Personally I think Alu-clad is a good idea.Alu-clad are the nicest windows you can get.They are aesthetically pleasing on the inside with natural wood covered in transparent paint which does not take away from the wood grain.On the outside windows are protected by aluminium profile which are powder coated.This gives longevity and protection from rain,sun and other elements.Powder coating is very easy to clean.These windows come in turn and tilt opening hardware.This hardware allows you to have a large opening sash.These type of windows are a new trend without any obstructing profile divisions
...I just saw lovely ones (Lituania iirc...), which are alu-clad outside, and he had planned on timber look inside, but at the last minute plumped for an ivory white interior frame colour. Looks gorgeous.