the 400ex is a good all around quad with excellent handling and a smoothe powerband and its extremely easy to wheelie, a banshee, on the other hand is outdated but wildly fast when you hit the middle of the powerband, great for dunes or fast trails, as for relablility, a banshee, being a 2 stroker has to be rebuilt more often than the 4 stroke 400ex and you also have to buy 2 of everything on a banshee seeing as how there are 2 cylinders, 2 carbs, 2 pipes, etc... its up to you, if you just wanna go fast all the time and drag race, get the banshee but if you want a quad thats more reliable and handles better but has a less explosive powerband, get a 400ex, im not bias to any quad company, i've had both yamaha and honda, just speaking what i know.