I bought both games this year. (Pc)
First i bought PES cause im convinced that it is the best PES ever.
Then i gave a real try on FIFA 17. My conclusions:
FIFA wins at:
-Ball physics. The ball rolls, spins, retains its spin, almost perfect. I would like it to have more weight but compared to PES is supreme. PES ball has right feel on weight, but its very basic on spin, and rolling physics are not convincing.
-Player animations. Tons of animations for every situation. Passing, shooting, controlling the ball. Pes is very basic in this sector, although it has progress this year.
-Footplanting. In FIFA dribbling with a player feels very natural. Especially in turns and stops. Feet are placed on the pitch right, adding to the realism. In PES there is TOO MUCH glide, ice skating, especially with top players. No inertia, poor footplanting
-Shooting. In FIFA, tons of shooting animations combined with advanced ball physics,produce a realistic variety and unpredictability. In PES this year shooting has more error compared to last year's PES, but still lacks in variety due to shortage in animations and basic ball physics.
-Graphics. Ok i don't have to expain much here. Every stadium in FIFA with different conditions and time, is a different experience, with almost perfect photorealism. Turf color, shading, ambient occlusion are spot on. PES on PC is very plain and feels old gen.
-Net - kits - hair physics. Very improved this year in FIFA. PES had awesome kit physics in 2014, but since then the plysics are gone. Also for nets, last PES with good net physics was 2011, since then it become generic and rigid.
-Goal scoring feeling. Shooting animations, ball physics+net physics combined is the reason. In PES, there is a slow motion feeling, especially inside the box and penaltied where everything looks like slow motion
-Sound coverage. Commentary and crowd in FIFA are top. Pes has better ball sound though.
-Authenticity/Licences. Nothing to explain.
PES Wins at:
-Players feel more "heavy" on the pitch. Althougth ice skating, gliding and bad footplanting kills it.
-Animation smoothness. In PES animations feel more natural and better stitched together. FIFA has issues in stitching animations giving a strange "trembling" feeling like puppets.
-Collisions. Feels more natural, and the balancing animations give an extra immersion point.
-Lobbed passing. Feels better in PES and more consistent.
-Skills/tricks mechanics. I prefer the skill system in PES because using two sticks makes it more difficult and thus rewarding. Also animations in skills/trick are better and smoother.
FIFA and PES are equal regarding:
-Passing. In FIFA passes feel more natural due to advanced ball physics and player control. But there is an unexplained inconsistency, especially in lobbed passes. In PES passing is very consistend, but they are to linear and straightforward.
-Overall gameplay. FIFA tries to be more sim, whereas PES provides more fun and randomness. It's a matter of taste.
-Goalkeepers:Both very good and consistend, but in FIFA are too quick in reactions, in the contrary of PES where they diving in slowmotion.
FINAL WORDS
I prefer FIFA for the reasons explained above. Its looks more next gen game almost in every aspect. But PES this year is the best PES since PES5/6 providing fun and unpredictability.