Oh boy here come the Ness comparisons.
To clarify on this, PK Fire has this sort of auto-spacing property where Lucas looks like he gets recoil when shooting PK Fire from a wavebounce, making it that much more difficult to punish. The poke damage he receives might seem negligible compared to Ness' free grab (though Lucas has other grab confirms so this property would be rather broken on Lucas), but it still contributes to the approaching kill throw / is much safer due to firing horizontally from SH / will frustrate your opponent to hell and back.
Here's frame data to compare the two:
http://kuroganehammer.com/Smash4/Ness
http://kuroganehammer.com/Smash4/Lucas
Overall, Ness has arguably superior frame data with the crowning victory being his aerial autocancels, Fair in particular. Lucas has better tools to wall his opponents out and deal with projectile-based characters with the positioning / hitbox of Psi Magnet, Zair (snuffs projectiles), and PK Fire; I'd say that this gives him better matchups against
but there isn't much top-level data to go by with these matchups (except HaKii vs Hyrule Hero; that looked like a convincing 60 / 40).
While Lucas' kill throws don't kill remotely as soon as Ness' Bthrow, they're all still contenders for some of the best in the game due to each and every one of them killing, and D-throw > Bair at the ledge is just... You feel bad. Like, downright ashamed of yourself.
On the subject of PKT, Ness' is better for kill confirms and as a combo tool, but Lucas' has the unique property of both invalidating airdodges with its lingering hitboxes and dragging the opponent with it; it can result in stage spikes or forcing a low recovery, which would be better if the endlag weren't god-awful, and at the very least is free safe damage against those with safe recoveries (you know who you are).