The VS4-10 is in a different league from the Gen8 and Element, as well it should be given the price. Out of the box, it has several features that make it a better comp rig than either of the other two, particularly its lower center of gravity (esp. the VS4-10 Pro) and more durable components. But it also has one drawback in a comp setting - the aluminum axles can hang up on rocks more easily than plastic axles. The SSD Trail King is also an excellent choice for either a class 2 or class 1 comp truck due to its low CG and high quality components. But that doesn't mean the Gen8 and Element aren't good. They are both good trucks for the price, and most of the weak points in both trucks can be addressed with appropriate mods and upgrades.
If you plan to participate in comps, I'd encourage you to focus first on learning to drive whatever truck(s) you build. I've participated in some high level comps and learned even more by judging them. I've seen people do very well with both short wheelbases and long wheelbases, light trucks and heavy trucks, high-powered brushless systems and old school brushed systems, max-height tires (4.75" for class 2) and shorter tires, thick shock oil and thinner shock oil, etc. There is no "best" or "right" way to do it. The best comp drivers understand how to work with the strengths and weaknesses of their trucks, and they learn how to make good decisions (e.g., picking lines, when to reverse, when to use a winch, etc.) on course with the clock running under pressure. Once you get some experience under your belt, you'll be in a much better position to decide what to build next and how to set it up to your liking.
