Don't buy an expensive carbon bike going from a cheap walmart one. In fact, buying a bike that is four times the price of a $300 walmart one will give you a whole lot of better bike than the Walmart. I like carbon fibre, titanium, kevlar, and all that, but you don't need any of that to have a good bike/boat/car whatever. In fact, at that price point, I'd rather have an alu bike (alu, because it doesn't rust, but if living somewhere dry or I only rode when it was dry, steel would do). I think it will run better because more of the money will be spent on components/wheels etc. than a cheap (for CF) CF frame where not much money was left over for components. Much of the advantages of CF only shows up in dearer frames.