I am a nekkid hospital birther, but I do like to "start out" in clothes LOL
I got a binsi skirt on sale when I was pregnant with my third and I have to say, it really did rock. With dd1 I wore a stretchy sport bra and nothing else, with dd2 I started out in a stretchy sports bra and a wonderfully comfy/stretchy maternity skirt from Target. With ds I planned on making a binsi style skirt but found that binsi on sale and ended up wearing it and a sports bra in early labor. Which is my plan this time round too.
Pros: The binsi really is comfy. I probably wouldn't wear it much while pregnant just because it's a bit shorter than I like my skirts to be for general daily wear (I prefer that a skirt hit where the calf starts to narrow, the binsi hits much more at the knee) and also because I prefer fuller/swingier/twirlier skirts... the binsi is a heavier cotton and while it hangs nicely it doesn't drape the way I prefer for street wear. I DID wear it a lot postpartum though because the way it's designed lets you lift the back without rumpling up the front/sides so I could sit directly on a chux or big ol pile of cloth prefolds without looking like that's what I was doing! LOL
The construction is really solid. If this is the style of skirt you like, then it's a skirt that will last a while! And since it has a drawstring it is very size-forgiving... it's going to look more or less like it looks on the models no matter how big or small you get. I was using it over swinsuits and as a "quick throw together" type outfit on days when the laundry wasn't done and I needed to go out. Sort of the skirt version of sweats?
Cons: The price! I rarely buy new clothing (underclothes and socks are just about it, and even then I shop sales) and the thought of buying an item that cost that much and might be worn only for a few hours makes my heart cringe! But kind of like with a wedding or special event outfit... if having a special, pretty, birth specific outfit will help you relax and enjoy your birth it's probably worth it. I know it gave me a psychological boost to put it on, even though I took it off an hour or so later to get into the tub.