I've bought about 4 or 5 games on here in Total from CDkeys, I think my first one was The Division Golden Edition for 80 Dollars almost a year ago, that one worked smoothly no problems, then I bought some DLC or some other game I can't remember for sure, that also was Valid, recently I bought not one but TWO Battlefield 1 Keys and they've also been Valid.
I've tried CJS CDKEYS AND THEY SUCK, DO NOT!!! BUY FROM THERE! THEY LIE ABOUT PRODUCT AVAILABILITY AND WILL SEND YOU REGION LOCKED KEYS SOMETIMES! I bought BF HARDLINE from them and it said INSTANT DELIVERY, ended up waiting like 1 - 2 days to finally get my code, I then bought MAFIA 3 on there cause it was the cheapest and SUPPOSEDLY was NOT Region Locked, It said AVAILABLE, INSTANT DELIVERY and when I bought it, not only did it TAKE 3 DAYS TO GET TO ME, IT WAS EU REGION LOCKED!!!
I love cdkeys.com so far.