I received mine yesterday. The iPad Pro itself looks brand new. It was packaged in a crappy non-Apple box with a new-looking 10W (?) charger and new lightning cable. There was no Apple SIM installed. I bought one for $4.99 from my local Apple Store and use it with a 12W charger I already owned.
It had zero battery charge when I got it, so I left it overnight to charge and set it up this morning.
I took it to an Apple Store today to check it. It was originally activated on Feburary 7, 2016 and showed 2 charges and 105% battery health.
Overall, a good deal. They have some more on eBay but the price is now $740 instead of $690.