Ryan Leslie? Uh Oh. Here come the wolves.
Sh*t that's a good response. I thought people forgot about his short Next Selection legacy back in the mid 2000s when he dropped "Just Right" in '05.
He's the best as an R&B producer and better as an R&B singer than a rapper I`m sorry. His career fell hard when he tried to fit in with everybody else in that regard.
I'd say dvsn's OVO in-house producers are the best because they capture that Trap Soul after-hours kinda vibe but other than that, there are too many DAW beatmakers and DAW producers out there
so this is rather an ambiguous question's shoes to fill with answers.
Now since I do Trap Soul as of late, which is derived from its most-parental genre R&B, I will say whom the best R&B producers are in the last 40-50 years:
James "Jimmy Jam" Harris III and Terry "Crazy Bassman" Lewis
LA Reid on drums/drum sequencing with Babyface on Keys and e-Bass syntheszing with Daryl Simmons on bass guitar as a winning team
then Teddy Riley with Bernard Belle and schooling Pharrell Williams and Chad Hugo. NOBODY BETTER NUFF SAID.
Okay honorary mention to Gamble & Huff, Quincy Jones, Kyle West, Foster and McElroy, etc.