I still prefer the 1st one though.
Pros:
-Main character has abilities that Alex don't have like tendril arms, bio bombs, spike shield, kill-consume, etc. and because he served military once he doesn't have to transform into military soldier to use a firearm or vehicles.
-Separated Health bar and Mass bar. So no more critical mass, which is better since it makes you invincible in the prequel.
-Hunter sense auto lock, you can easily lock on your prey and leap at them from afar.
-No more flying viral detector.
-The game will warn you when someone else see you're going to consume somebody. to prevent instant alert.
-New enemy types, Juggernauts, Goliath, and fellow prototypes called Evolved.
-All the abilities are balanced, blade arm are not overpowered, and whipfist can now do some real damage against bigger infected.
-Groundspike devastator replaced with an ability to summon up to 5 brawlers.
-Larger city, and a new feature to move to another area easily.
The cons:
-He also don't have some of Alex's abilities, musclemass replaced with tendril arms, no armor, no explosive recovery, no air stomps, no elbow drops from wall.
-You can't walk with shield anymore.
-Less side missions.
-Said missions is almost always the same.
-Shorter playtime, storywise.
-No focused tendrils devastator.
TL ; DR
Only get it for the story.