Very Poor. Sent my games in January 2018 and still not received anything 6 months later, despite them receiving an acknowledgement from them that they have received the games.
I've used three different game exchange companies at the same time to maximise my money and these were GameXChange, Ziffit and Music Magpie.
Music Magpie sent my money first - within a couple of weeks and Ziffit a few days later.
Several months later I am still waiting for my money with GameXChange and I'm chasing them. Constantly being fobbed off with different excuses, ranging from "we're really busy and it'll take a couple of days", to "there is a problem with the payment system".
AVOID THESE AT ALL COSTS.
I certainly will do in the future.