I need an advice on which mountain bike should i buy?

The Raleigh specifically states it uses a cette rear cog. The Diamondback doesn't say. A cette is a much better set up than a freewheel. Other than that...both are priced about the same. My own personal choice is Raleigh. But, buying a bike is a very personal experience. I'd ask if the Diamondback uses a freewheel or cette. Then go with your gut feeling...which one fits you the best? Which one do you feel more comfortable on? Try before you buy!