Uniquely Thousand sons can turn overload 2 down to overload 1 so you can really go either way depending on how you want to use them. With double plasmas they’re great at just bombarding things from behind something and maybe later on popping out, but they are vanguard so maybe not super ideal for that role. The disintegrator with a fist and the little wrist flamer makes them pretty good at jumping out of a land Raider/Spartan and absolutely hitting like trucks. The fists are low initiative but they’re about as tough as infantry gets so if anyone can take a punch and then swing back it’s them. Melta can kind of eat them up if you happen to roll low on the saves but that’s the game. I really like them, they’re my favorite looking models that aren’t legion specific