I have both - French doors that open into my sunroom, then sliders that open from my sunroom onto my deck on one side, the patio on the other side. I have double sliders that open from our walkout basement to the screened-in porch. I prefer the sliders to the french doors because they don't take up any clearance space and they seal tighter in the winter. I had all french doors in my former house and they were drafty. I used them in this house in places where they wouldn't be exposed to the outside (great room to sunroom, main hallway to office)and because they gave me the same effect as a Nana wall at about 1/3 the price.

Thanks Jackson. That is my gut feeling as well. The lower price of the vinyl is so appealing but the FG seems like the better investment from a maintenance and repair standpoint,, and even aesthetically. I haven’t found any vinyl devotees that can provide a counterpoint.

mirror and frosted mirror are more economical than most clear or frosted glass. But the cost difference is small enough that when they go on sale at big box store, it easily swaps or evens out. Tinted mirror is expensive as they are not as popular.

Threshold reducers can get very tricky when the sizes are off. Consider Schluter Products Vinpro-U https://sccpublic.s3-external-1.amazonaws.com/sys-master/images/h76/hf2/9341303062558/VINPRO.pdf It's clean and easy. All different sizes and used everywhere. Basically is invisible when installed.