I have no experience, but I've spent days and days perusing this and other forums, so I will pass on what I've read. (I, too, am in the market to purchase a bike, in my case after decades of not riding.) According to "everyone," all big box and department stores, even those such as LLBean, sell bikes that have components far inferior to the bikes sold in bike shops. They are much heavier, not built to last, and you will die if you spend more than 15 minutes in their vicinity. OK, I made the last one up. Supposedly, Schwinn is Schwinn in name only; some dude bought up the old brand names and now they are just cheap BSO's (bike-shaped objects). Not the Schwinns of our youth at all. Or so "they" all say, quite convincingly I might add.
I have read this repeatedly and am now looking to buy a low-end "bike shop" bike (Giant Cypress or Sedona), although there is no bike shop where I live. So I have been convinced. I do have acquantainces who quite happily ride Walmart and Target bikes, but I'm sure their bikes will disintegrate into dust at any moment. I don't know the specifications or specific reasons you mustn't buy these bikes, but you mustn't. So there!
Good luck with your purchase! I'm still perusing forums and driving everyone here crazy asking questions.