@newbostonconst That's a valid concern. However, it depends on the profile you choose. There are many with frames thicker than Americans are used to but others with slim, minimalist ones (e.g. Twinset View series) where the casement is concealed in the frame when closed. Definitely a matter of taste.

Alside windows may be worth a look. Custom builders around me are using pretty basic Jeldwen or Andersen and the Alside have same/similar performance (or better) at a better price point. I've used them a couple of times and they seem to be a good value and perform well. My last blower door test we did not have any leaks through the windows that were noticeable with the smoke pen.