i had a mongoose mtb from walmart... it was cheap and all the problems people mentioned are true, but i still enjoyed it and rode it alot. By the end of <500 miles (on rough trails mostly) my 24 speeds became approximatly 12, and after a few crappy brake moments (i swaped out for a pair of $15 kool stops up front, these are top of the line brake pads that make crappy brakes respectable), and i bought $20x2 seferas tires because the no name tires on the bike yields a flat everyother ride (again going over rocks and logs). the bike operated safely. I gave it to my younger brother and he enjoys it alot.