I have just had my wife try it on her phone, EE 4G, and she is getting ping times of 70ms, so in that practical test it matches their stated expectation, but I see better than their stated 100-125 on 3G, Typically I see 50-80 ms (on the Three network) looking back at my speed test results in the speed test app. I guess time will tell if on average 4G is better in this respect, but it does not immediately lead me to think that you are going to be seeing ADSL ping times from 4G.
But all that said it works well enough with these time, so if I were the OP it would not put me off getting a PS4!