OE 9" center sections are not adequate for any decent power level or abuse. And stock housings are kind of flimsy as well.

Gear ratio options, aftermarket support and development, ease of maintenance, all steel housing, strength with proper prep, all favor the 9.

If I were doing a Mopar for a reasonably close to stock chassis, leaf spring, street/strip deal, where the ratio doesn't need to be dialed in exactly right and where I didn't want to spend 5K, I would use a 60.

Race car, tube chassis or back halfed, narrow 4 link, busy and/or fabricated housing with lots of stuff on it, need to be kept light, need to dial the ratio in, 9" all day long.

Somewhere in between? Depends.

It's not so much one is better than the other, but depending on the intended application, one or the other will probably be a better choice.