I figured I'd throw in a buyer's perspective (though I do have a bag for sale there, too). I bought my first item from Tradesy at the end of Feb and got it today.
Overall, it was a mixed and kind of stressful experience for me lol. The item I bought is a LE Louis Vuitton. I'd been searching for it on several sites, but decided on Tradesy because of the authenticity guarantee and that if I needed to return the item due to it being fake, I wouldn't need to pay shipping. I also found the bag I wanted on there in good shape for a good price and free shipping. So I bought the bag. A couple days later, I get shipping confirmation and find out the bag is coming from China. There was no indication on the listing/after I bought the item that it would be coming from China. So that made me nervous because a) what if it's a really good replica and b) am I going to get slapped with customs fees. Ugh.
I had planned to get it authenticated after I got it because I was afraid the listing photos would not be of the actual bag. The whole "four days to return" thing is pushing it a liiitttttttllllleeeee bit for authentications, so that also made me nervous. So, hoping to speed that process up, I tried to get the listing photos authenticated on the forum and then would provide more photos when I got the item. But Tradesy requires you to join to see the item, so TPF authenticators couldn't do it. Ahhh!
I work M-F 8-6:15 with commute time factored in. Of course the bag arrives Friday and gets taken to the post office since I'm not there to sign. I pick it up this morning (no fees) and it's GORGEOUS! I love it! It looks and feels good to me, buuuutttt this is my first LV, so what do I know. I take photos to get it authenticated by a paid site and get a quick response that it's real. Phew! Buuutttt all the posts I've seen about fakes fooling authenticators makes me nervous, so I'm waiting on a second opinion.
The status of my order on Tradesy does not show that I've picked up the item, though I told the seller (twice) that I did. So now I'm wondering if the 4 days is from Friday when it got to the post office or today when I picked it up.
Sorry that was such a long, rambling post, but I just wanted to share my experience. Overall, I think Tradesy is a good site, but I really wish a) I would have known the item was coming from China b) the 4 day policy was extended a bit for items that turn out to be fake because not all authenication services provide that quick of a turn around c) you didn't have to join the site to see the items