Ursaring is awesome, but it's on a timer when it's functioning at its maximum.
Ursaring is the most powerful Facade abuser in the game, allowing it to smash through anything and everything that is not a ghost. Ursaring's movepool has everything it needs: Facade, Protect, Crunch, Close Combat, and Swords Dance. Ursaring also has the abilities to turn anything into slug juice: Guts and Quick Feet. With a base 130 attack, Ursaring is not even close to lacking in the power department.
Two major things hold back the grizzly: Type and stats. The main reason Snorlax dropped to the UU tier was its type: Normal. Ursaring has huge neutral coverage with STAB Normal, but no super-effective hits. The Normal-typing also brings no resistances (though it has an immunity to Ghost) and a weakness to Fighting, which is seen more often than the number of people that try to text on their cell phones in the middle of classes. The downside to Ursaring's stats are everything except that awesome attack stat. 90/75/75 defensive stats aren't bad, they are just not enough, given the fact that Ursaring has no resistances. That base 55 speed is not doing Mama Bear any favors either (Quick Feet does help).
There is one other problem: residual damage. Ursaring will function best while poisoned or - if using Guts - burned. That puts Ursaring on one really big timer. It can only be used so many times. Add Spikes, Stealth Rock, and Sandstorms, and Ursaring won't be seeing much action.
If you are too close to Mama Bear's cubs...
Nature: Adamant
Ability: Guts
EVs: 252 attack and HP, 4 speed
@: Flame Orb/Toxic Orb
Facade
Crunch
Close Combat
Protect/Swords Dance
Mother bears are deadly when they are with their cubs, and this one has Guts. This set offers unrivaled power, designed to turn walls into onion vapor to make enemies cry. Facade is the power on the set. Crunch hits spirits, Close Combat hits rocks and metal. Protect ensures safe activation of your chosen status orb, but Swords Dance can be used if you really think you don't have enough power. Flame Orb will make Ursaring last longer, but is a dead giveaway that Mama Bear has Guts. If that worries you for some strange reason, use a Toxic Orb.
If you want to use Mama Bear on a Trick Room team, you can move the speed EVs to defense or special defense and use a Brave nature. This will patch up Ursaring's lacking speed while still using that godly power. Just remember to swap Close Combat for Hammer Arm.
...Papa Bear won't let you escape.
Nature: Jolly
Ability: Quick Feet
EVs: 252 attack and speed, 4 HP
@: Toxic Orb
Facade
Close Combat
Crunch
Swords Dance/Protect
Same exact moves right? Yup. Purpose? Completely different. Papa Bear tries to be a sweeper with the speed boost from Quick Feet. No Trick Room option here. Move-wise, Swords Dance is the preferred option over Protect. As long as Ursaring switches in on something that it can survive against and outrun after Quick Feet, Papa Bear will be monstrously powerful. If you want to play safe, Protect is just as good of an option.
I will make one thing clear: Ursaring can turn Toxic Spikes against you into a major advantage, especially if there is only one layer. Vanilla poison does less residual damage than Burn, and does not have the damage increase of Toxic poison. If status (not named paralysis) is being a problem, Ursaring can turn that problem into one very big advantage.
By the way Serebii, your statement about Ursaring having some decent abilities that allow it to do SOME decent damage? I think you are being a tad modest. Just thought you should know.