I am truly surprised at the attention this thread is getting, so apparently the content has merit.

My opinion is that if you want a cheap ride, unsure of your level of interest, a true beginner who might think all bikes are created equal or maybe just buying a bike for your kid to abuse (unknowingly, just being a kid) or outgrow, then a big box bike is perfect for the situation.

Should you think those bikes are good enough for you, take the time to get them properly checked out before heading out for a ride, unless you can do that yourself.