I personally like the their feedback system, it does seem quite transparent. I would just say to check just how much feedback there is, I mean 100% with only two feedback means absolutely nothing really.
If they have been trading for two years, they should have decent numbers to judge them by, but remember to also read the comments left by their customers as well to give you as much insight as possible.
I would always recommend buying a sample of whatever it is you want to sell, it's no guarantee of your customers getting a good quality product, as plenty of suppliers are smart enough to send you the good one to test, then send your customers garbage.
No guarantee, but at least if they send you something you don't want your customers to get, then you know to steer well clear.