Ruckus is a jack of all trades. He can build more towards damage, support, or tankiness. Either way, his miniguns are contenders in the "Top DPS" market, and any Ruck can deal a surprising amount of damage in a short time. If he ults, just run.

A Zhin can get a lot of counters off of Ruck before the Ruck even understands much of what's going on. If Ruck ults, you can get him to completely turn away from your team if you just stand in front of him with counter up (and the counter legendary.)

A good strategy for this encounter is to hit Zhin with your poison bolts first. Most Zhins will panic counter or billow. After that, it's very easy to burst him down with basics when his defenses are used up.