TLDR: Excellent stickers & customer service.
After some online research and good reviews, I ordered two sets of the 3 inch stickers to try out for my small business. There was a small snafu with the files and I ended up with the same file twice. When I reached out they were quick to respond and sent me the other set of stickers, which arrived surprisingly fast.
The quality of these stickers has been great so far, I've been testing them on my heavy use hiking water bottle. I got the matte finish, the colors are nice (important because i'm an artist), edges lay flat, and they really seem to be waterproof.
I will definitely be ordering more of their stickers for my art business!