We actually suggest a 3rd option: Marvin Windows & Doors, specifically their Integrity Line. Very high quality. They last forever. (Because who wants to get new doors and windows more than once? Haha.)

https://www.marvin.com/ 

A-series and kolbe are nice, Marvin is highly regarded and don't forget about there Ultima line.

I would go with the A-Series personally of the options you mention, but why not look at the Andersen 400 Series also? They are made in custom sizes as well and less expensive.

We were told that A-Series were better made vs 400 Series, but we haven't gotten any deeper as to what makes it better.

Would not say there made better but differently.They are more definitely more complex and made with more expensive materials. The biggest visible difference is the exposed vinyl jambliner on the base 400 series and available exterior colors. Performance wise they are very similar. If you look at them in person you can easily see. The 400 Woodright is very similar to the A-series. The A-Series is also easier to tilt in for cleaning and takes less force to open and close.

Marvin, Kolbe, and Andersen all have solid offerings, I personally prefer the first two in most cases.... I would not put the Sierra Pacific in the same league as the other IMO.

Can't add much to the list beyond the brands mentioned already. If you stick to the several that were mentioned multiple times above, you are in good shape. I am guessing you are looking for that wood "look"? The A-Series is a vinyl composite with wood floor material.

The A-Series has mostly a wood interior, the sashes are fiberglass with a wood face and the frame is Fibrex over wood. An interesting combination indeed?

I like aluminum clad wood windows , Iwould try to keep custom sizes to a minimum and use custom where they are most needed.

Don't use Marvin. We did and it was a horrible experience. If I could do it over, I would go with Andersen.

Very few manufacturers have "standard" sizes anymore. Most are custom order down to 1/4" or less, including wood clad. Sliding doors still run standard sizes, but not many windows.

While I agree that most are available custom order, HomeSealed-the cost can jump significantly if it's not in the 'standard' grid for some manufacturers. Especially clad wood product.

Ah I see. We deal with mostly Andersen products overall-and they tend to up-charge for custom sizing on their mid to high line offerings.

That makes sense qe, my dealings with Andersen in particular are relatively few and far between as of late