I'm currently doing SS. There's a guy who works at my gym and he came up to me today and asked how I was progressing with squats. He also said he was looking at me for some months and that that what I was doing seemed good. He then started telling me about 5/3/1, which he does. He has some good lifts. Squat was over 300lbs, deadlift almost 400lbs. He wrote the entire program for me on paper with my 1RM's. I'm doing SS for 4-5 months now. Should I switch over to 5/3/1 anytime soon?