I think that one of Lomu's greatest strengths, and underrated at it, was that he knew when to have a go at someone and when to go around it.
Tackling someone who is coming at you requires a specific type of tackle and posture from the defender, different from when someone tries to get around you. Lomu was very good at both but he was extremely good at mixing it up and taking advantage of the wrong call from the tackler. If he saw the tackler was firmly set to take the hit he just went around him. He did so a million times.
Of course he could go full own against some of the best defenders and smash them too, no doubt.
The tuilagi's are not even remotely close as fast as Lomu was and rely much more on power. Not saying the are slow, but just to give you a tangible example, Manu is probably slower than most back three from all tier 1 teams. Lomu was probably faster than most back 3.
This is important because it gives the defender an option: if the defender is fast enough and he is not cornered into his try line he can let Manu pass, avoiding the hit and get him from the side. He will lose a few meters from the momentum but he's got the job done. If you took that chance with Lomu odds were you couldn't catch him.