I use IF Marcal in a French/Ligue 1 squad so LB options are very limited but he has been tremendous ever since I picked him up. He is by far the best left back going forward I have ever used because of his combination of pace (which is even better with a shadow chem style), pretty good dribbling, and his absolutely deadly crosses. His shooting isn't half bad either because of his 86 shot power. Defensively he can occasionally be caught out on the counter because of his work rates and poor marking and he also sometimes struggles to bully players off the ball with his low strength. However, with the shadow chem style, he is an excellent tackler which helps make up for his defensive shortcomings. Additionally, he will win most aerial duels he faces which I really appreciate in my fullbacks.
Overall, going forward he is the best left back I've used with better offensive stats than the much more expensive Alex Sandro (who I use in my Serie A team) but he can sometimes disappoint on the defensive end as compared to Sandro or the IF Roussillon.
Marcal's IF card has some really good stats to look at, but in game, he feels really, really average. I had Adriano before replacing him with Marcal, Adriano feels just as good, if not actually a bit more solid defensively. Marcal has a bit more pace, but he definitely struggles to keep up with other players who have less pace, such as Yarmolenko or even Bernardo Silva. His standing tackles feel very hit-and-miss, and if you attack, he often takes a while to get back to defend because of the medium defensive work rate (I don't even use him on 'always overlapping', if I did this, I feel he'd be even worse). When he has the ball he feels good to run with, but as a LB, it seems almost pointless most of the time, and in general, the stats he actually needs as a LB simply aren't there in-game.
Passing is decent; crossing is quite good
Pace is definitely not 85
Doesn't track back to defend quick enough
Standing tackles are very weak, doesn't seem to be able to make tackles and often is slow to react
Strength is horrible, very hard to make challenges with him or attempt to push a player off the ball
When he does get into the box, the shooting is pathetic, cannot finish (bad stat), but even his shot power doesn't seem to reflect the rating