They are two extremely similar guns. More similarities than differences between them. Size-wise, they are practically identical. Weight wise, the Sig is only 1 oz heavier. Both guns have 4 inch barrels. Both guns are heavier and wider than all of the popular full size pistols that use Striker type pre-loaded trigger systems, like the Glock, S&W M&P, or Springfield XD ( except for the super large Springfield XDm model ). Both have polymer frames, and both have DA/SA trigger systems.
The Beretta PX4 full size is 100% made in Italy, while the Sig 2022's frame is made in Germany, with the slide and barrel made in the USA. The Beretta has a slightly lower bore axis, and has a more complex rotating action that is designed to soften and control recoil better. Some feel that the extra complexity of it, though, makes it inherently less reliable.
If you want a full size gun with a polymer frame and DA/SA trigger system, they are both great choices. Both the DA and SA trigger pulls on my own Beretta PX4 are optimal for defensive shooting, in my opinion. Very smooth, and not too heavy, and not too light. However, Sig trigger pulls are pretty good too, though.
Best thing for you to do is to handle both guns, and see which one has the better ergonomics that you prefer. The very best thing to do would be to find a place where you could rent and shoot both guns.