TL;DR - They are both very good weapons IF you understand their weaknesses and work around them.
If you're talking about a straight up 1v1 fight, you'd want to consider range and mobility, as well as precision. The .96 has greater range, equalling that of a Splattershot Pro and Dual Squelcher, but tends to perform poorly at that range due to its lackluster accuracy; keep in mind that this weapon fires very slowly, so missed shots are much less forgiving. It also has painfully slow run speed whIle firing, in my opinion. The .52 has less range, but cranks up the fire rate to give it one of the fastest ttk if the shots land, as it's still a 2 hit KO. Keep in mind the .52 is extremely vulnerable to defence up perks, and a single defense up main or three subs is enough to make this a 3 hit kill. In ranked you tend to see people with absolutly no defence, or defense stacked to the moon, so how you organize your abilities is up to you.
The .96 and .96 deco are still great weapons for support and balls-out frontline offense respectively, just try to mitigate the weaknesses. If you like going HAM on the opponents and getting right up in their faces, go for the .52 and you won't be disappointed. (Try boosting mobility for this)