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.
Ruckus can activate a shield, if you are finding it hard to kill him then purchase "wrecker" from the item shop, getting it to tier 3 shreds through his shield.