I purchased this ATV at the beginning of last summer. I wasn't looking for a race quad, or the fastest ATV on the planet, I was looking for a trail ATV with good performance, handling, looks, and above all, reliability. The 2009 Trx400x is exactly that. Honda is known for their reliable products in anything they sell, and the Trx400x is no exception.
There is definitely no lack of power and the throttle is very responsive. After only a few hours of riding you get an amazing feel for this quad as the handling is perfect. The way the quad is shaped you can really slide it through corners and fly through the trails. I personally love the plastics and it really stands out. I don't do any extreme four-wheeling or go through 4 foot mud wholes, or hit giant jumps, so the suspension is exactly what I am into. It is THE king on the trails and I couldn't ask for anything more from it. It is also bullet proof. I haven't had a single problem with it, and I do ride it a lot. It requires much less maintenance compared to most 450s. The only downside is that it doesn't have as many bells and whistles like the Suzuki z400, like EFI (Electronic Fuel Injection) or liquid cooled. But even without having EFI, i still have yet to have a problem starting it on a cold day, and the throttle response is still great. You may think it might not be able to ride all day without overheating, but for some reason and in the way this bike is designed, it has yet to overheat. Even after a solid day of non stop riding. And it may not be as fast or as powerful as a 450 race quad, but thats nothing a few aftermarket parts cant fix, as there is a TON of aftermarket parts offered for this ATV. Myself i couldn't care less about keeping up with them, and the only after market parts i would consider is a good set of nerfbars, some powermadd hand-guards, and a nice slip on pipe. This way you still have a mean looking, great performing, beast sounding trail atv without giving up it's reliability.Because once you start getting into the heart of the engine and changing a ton of parts, is when reliability decreases.Another nice thing to add would be a nice new set of tires, as the stock tires lack performance.
All in all, this TRX400X is the perfect atv if you want a reliable low maintenance quad, with an extremely high fun factor as it lacks nothing. It is also a really easy ATV to just jump on and go, so it would make an excellent ATV for someone who might be just getting into ATVs. Yet still has everything you would want if you've been riding ATVs all your life.
One other thing to note, is that Honda hasn't made any 2010, 11, or 12 models, so any new TRX400X you find are the ones just haven't sold yet but there is plenty out there. The MSRP is around just over 6000 US, but since dealers are trying to get rid of them. You can probably find one for around 5000. Also, the 08 models are practically identical, and there are still some around, so if you find one, you can probably get it for just over 4000.