UFCW is very much a business union. On occasion they'll do cool things, but it's far from a guarantee. Large business unions like the UFCW are also generally more willing to reject leads.

If you and the other workers want a contract, and are reasonably confident you can get one, go for it. But around half of all Union elections fail, and a surprising number of unionized work places can't manage to get a contract (though you might have better luck with your independent store). In regards to those malicious management tactics, they might help file a ULP, but that's very dependent on your local.

A lot of the alternatives are smaller, and as such kind of location dependent. Like with the IWW (which is tiny, compared to most unions), if you're near a good branch, it's great. For example, the IWW in San Francisco has quite a few shops unionized (keep in mind that there are usually more IWW shops than advertised, a surprising number of places like to stay under codename). Sometimes cities will have smaller "independent" unions, that focus organizing in just one area. Other places have coalitions of unions that might be willing to help you out.

One thing to consider doing is to just reach out to a number of organizations and unions, without necessarily committing