Here we go again, and I am going to give the opinion most on here don't like. I ride several 1000 miles a year on Walmart bikes. If you are willing to do your own adjustments, maintenance, and don't care to ride for speed or in a group, they can do just fine. And go into an LBS and you'll see all kinds of LBS bikes in the shop getting repaired and tuned up, In fact, it's repairs that give many LBS their profit of margin.
I've toured to Texas on a Walmart bike. Hauled groceries etc... Walmart quality bikes is all you will see in countries like China where EVERYONE rides their bike out of necessity or even our local chicken plant will have dozens of bikes, all of them Walmart bikes.
They aren't for everyone though. Sizing can be an issue, especially if you are tall. If you want to ride in a group, you will be snobbed anf eel out of place. And they are heavy compared to an LBS equal.
If you are looking into a Walmart bike, why not buy one, if you don't like it, return it. It's not a big investment.
Has anyone out there purchased or ridden the Schwinn Admiral that's offered at Wally's**********?? If so then what's your opinion of the overall bike and ride??
Just for me, they make me sit up in too high of a position with too wide of a seat and I prefer a flat bar with an add-on of bullhorns. I think it only has a rear derailleur and a single cog in the front. Nice rack on them though. Again, you can buy it and return it if you don't like it.
Good luck in whatever you choose and happy riding.