Mast is by far my favorite. I get minimal sides. The sides on npp make it not worth it for me. If strength is your concern run both. Or add in some tren.
I’m with you...at 25 I’d say npp all day. Now at 35 I’d say mast. It’s onviously quite mild but I could be on it 50 weeks and the biggest side is a 4 point on my hdl.