After seeing how he's returned from what is generally a career ending injury, the answer is clearly Durant.
If you want a player that will fill up the stat sheet en route to making your team a sure fire title contender? Go with LeBron. However, if you want an ATG team or potential dynasty, you take Durant & you don't look back. LBJ can't pass, initiate an offense, or control the pace of play well enough to be valued over Durant's ability to play at an ATG level without diminishing, and/or taking away from other All NBA caliber players.
It doesn't matter the context, Durant's unique(literal one of one) combination of size, skill, and shooting ability makes it so easy for him to score, you can pretty much slot him on any team and they'll be competitive simply by virtue of him being indefensible. Need proof? Look at those poorly constructed OKC teams, where he played without spacing, shooters, and a poor decision maker at PG for the majority of his tenure. They reached the WCF Finals or Finals every year he was healthy until he left for GS, and haven't been relevant since.
And what did he do with GS? Only elevate them to arguably the greatest team of all time, rivaled only by Jordan's Bulls, Shaq & Kobe's Lakers, Bird's Celtics, & Showtime. At their height, the Warriors were far and away better than any team LeBron's been featured on, regardless of how much input he's had on rosters, or how many HoF teammates he's played with. Despite it all, he's never been able to lead a team to a level of consistent dominance that we witnessed from GS.
Before I receive the usual rebuttals, I'll address them now:
- GS won before Durant, but only because Kyrie & Love were hurt in 14-15. Had they played in series it's reasonable to assume Cleveland would've beaten them, given they did so the very next season.
- After going 73-9 in the regular season, 15-16 Warriors limped through the playoffs, losing nine games in the total before ultimately losing the finals. The 17-18 Warriors lost one playoff game.
- If you put LBJ on that GS in place of Durant, he'd take the ball away from Draymond & Steph, change the style of play, etc. They'd be a completely different team than they were with Durant.
- Durant was clearly GS's best scoring option when games slowed down & defenses got tighter in the post season, which is why they pursued him to begin with.
Now he's doing it again with Brooklyn, a franchise that has never won an NBA title, with teammates who are allegedly cancerous & problematic. So much so, that pundits, analyst, and fans everywhere predicted they'd implode upon construction. So much for that, eh?