No, it isn't. Warframe doesn't have some elite class of gear that is "The Best," like Destiny has. There are weapons and Warframes that excel in certain areas, but they all have their own advantages and disadvantages. All weapons and Warframes can be made incredibly powerful if leveled and modded right. Buying your gear does not gain you any advantage over someone who earns it in-game. All gear starts out fairly weak, no matter whether you buy it or earn it. So, the player who chooses to buy a particular weapon will end up with the same thing as the player who grinded for resources and built it in-game. You cannot buy your way to fully leveled, overpowered gear. You have to earn it just like everybody else. All the microtransactions get you is the ability to circumvent some of the grind.