I nearly never tried Umtiti because (as I imagine many other people have done) I looked at his height and pace and thought he wouldn't fit the game. You're usually looking for those tall yet fast CB's like Varane or Sanchez. But after being surprisingly disappointed by Varane and Ramos (they weren't bad, just expected much more), I decided to give him a chance. Now I have over 400 games with him and he's one of the oldest players in my club. Imagine having Kante in your defense but he can also win the majority of headers, that's Umtiti. With a Shadow chem he feels faster than 89 Blanc with 79 pace, and he's just incredible at making interceptions and standing tackles. I've always partnered him up with someone who's good at winning headers just in case, but he seems more than capable himself anyway, I've never had any troubles with corners. And just as an added bonus he has great outfield player stats for a CB too. Decent passing and dribbling with a great long shot which has actually got me a few clutch goals when he sits just outside the area for cleared corners.
TL;DR: Don't let the height and pace deter you, he's just one of those players that plays so well in game. It's like having a Kante at CB that can win headers. Most overlooked player in the game IMO
Pace (Combination of Shadow and being only 6'0 makes him feel quicker than even the fastest defenders)
No cons honestly, obviously being a bit taller might help but then I feel he wouldn't have that unique nippy and agile Kante feel...