4G is basically just as good as a moderately fast home internet connection. My grandparents have Verizon 4G home internet(where they install a antenna on the house) and I dont get any lag spikes or anything while playing on their internet. I do get slightly higher pings(50-60 to my tf2 server from home, 60-75 at my grandparents), but the ping itself is completely stable(or as stable as any other Wi-Fi connection). Of course, this is with a good connection and a stationary attenna. If you were riding along in a car or had a poor signal, you'd probably have some latency issues.
Billy Mays: July 20, 1958 - June 28, 2009 The Greatest