I'd join and be active in it. A quick Google search shows me they aren't afraid to strike. As an employee, you'll be much better off negotiating with your employer through a union than you would individually. If they turn out to be littered with beauracracy and corruption you can hassle them at meetings and vote against the leadership. And if the union is corrupt you can make sure the membership at your store isn't, anyway.
If you're active you'll have a lot more influence on the union.


