What is the difference between a high or low end bike?

Answer 1

In high gear the rear wheel makes about 4-5 turns for each turn of the pedals, and in low gear the rear wheel might make less than one turn for each turn of the pedals. High gears makes you fast and low gears make you strong. Low gears are easier to push, so they're good for going uphill. High gears lets you put power to the wheel even when you're already moving fast to go even faster..

Answer 2

price, quality, weight, durability, reliability...of course there comes a point where the law of deminishing returns takes over...