I'm ashamed to admit that I have been to that place. But I have lots of friends in Alabama, so it wasn't too far out of the way. I'd also like to say that I am not much of a Goodwill-type store (thrift shop) shopper.
That said, I was totally unimpressed with this place. I'm not sure what you're looking for, but too me it seemed like a picked-over garage sale.
I have been there. I had an afternoon off after a business meeting in Huntsville. The hour ride was enjoyable but the Unclaimed Baggage Center was a real dissapointment. The majority of the merchandise was salvation army quality clothing. The luggage department consisted of six old and wornout 1960s type suitcases. The best department was the area where they sold boxes of hotel soaps and shampoos, we all probably have plenty of them.
If you have nothing to do and are close by it may be worth a stop for its tourist attraction value.