I don't have these specific booties (I have the Feathered Friends down booties & overbooties), but I can tell you after first using them I was kicking myself for not getting them years prior. The $100 price tag kept me away for a long time. Don't let the same thing happen to you! If you treat your gear properly they will last you a long time, so the sooner you buy them the more use you will get out of them :-)
As for use, I bought them for Fall through Spring camping. I expected to use them in my sleeping bag for extra warmth, and slipping on the overbooties for midnight calls.
I did indeed use them for this purpose, but I also ended up wearing them outside a lot during pulk camping. Since the ground was covered in snow, I think it was less abrasive than dirt/rock/plants. They're not meant for walking much, but I wore them and even jogged in them with my dog. (I had soaked my part-leather hiking boots the day before due to warm snow, and they were frozen solid the next morning. Hence why I initially wore them beyond the tent area.) You step a little differently in them.
Also, I always wore socks in them to keep them cleaner. I don't think everyone does this, but personally I hate washing down. I always wear socks (prefer toe socks) in my sleeping bags, so it wasn't a change for me. My feet get cold easily and take a long time to warm up, so down booties are enormously helpful in keeping my feet warm until I am in an active phase (feet are warm in while snowshoeing or hiking due to exercise, not while sitting around in shoes/boots cooking, but if my feet are very cold they may never waem up enough during exercise in cold temps).
I don't have the Goosefeet Gear overbooties, so maybe someone can comment on how the ToughTek overbooties compare. My FF overbooties weigh 4.85oz for the pair in medium. The down inners weigh 4.3oz. Total weight for medium is 9.15oz. GooseFeet Gear Booties are are only 4.3oz (20D booties & Dyneema overbooties).
So, GooseFeet Gear booties are less than half the weight for the same price as the FF ones! Adding 50% overfill adds $7 here and 1/2 an ounce. I couldn't find figures as to the weight savings if 10D versus 20D on the booties. Maybe I will make a separate comment for that.
Anyhow, I highly recommend down booties with a down inner and campsite-safe outer liner. I think the GooseFeet Gear ones are probably best for Spring through Fall, when you area carrying the weight on your back, and where the ground is snow-free. In winter (where I live, anyway!), pulk camping, weight is less of an issue, so the extra ounces of fabric and down and durability of the FF are worth it. One of the reasons I bought the FF ones is that I could go to their store in Seattle and try on different sizes. I'm a women's 7.5, wearing 8 in athletic shoes, and I chose medium in FF.
For most people here, on Massdrop, I think the GooseFeet ones are probably the way to go. I would definitely get the Dyneema over the ToughTek though.
For me, I'm debating whether or not I want to order an ultralight set here, or just $45 Dyneema overbooties from GooseFeet Gear's website and pair them with my heavier FF inners... hmmm...