I think you should avoid anything that's a mountain bike with a suspension fork because in your price range they are all crap. I think you would be well served by a hybrid that has fatter tires and mountain bike gearing. 32mm tires will give you a smooth ride on the road and you'll be able to ride on gravel paths. I agree with the ability of xmart stores inability to assemble bikes properly. The qualifications for those positions are probably "knows how to use an adjustable wrench". I think it will be worth the $50 or so that a real bike shop will charge to assemble.