New Windows, New Siding

We have wood casement windows, several years ago I was told I wouldn't be happy with vinyl windows, I think I was told because they sweat, is this still the case.

Also, need to replace windows now and plan to replace aluminum siding in a few years. Should both be done at same time or doesn't it matter?

That comment about vinyl windows is pure bunk. In fact, a good vinyl windows will often have better performance ratings than other materials, including in the area of CR (condensation resistance). Ultimately, there are a lot of factors that go into whether or not you will have condensation, but having a vinyl frame is certainly not one of them.
On the siding, it can be nice to do it at the same time as it makes a full tear-out easier if that is the route that you prefer, otherwise is does not make too much difference. The window wraps may need to be redone depending on circumstances.

it is nice to do the windows and siding together.
Doing them together will eliminate any duplicate work.
Most very good guys are ok with doing either before, together , or after.
When we do it together, we remove the windows first, set the new windows and then run the siding.
Vinyl or fiberglass best durarbility and thermal performance.

I have to replace two small windows now, bath and laundry in the back of house. The rest can wait until we're ready to side. I saw the Polaris Ultra and and Seaway Signature today. Cost of both about the same and dealer's preference is the Seaway, hard decision.

Polaris ultra all the way