I guess it depends on what you want to do with it. The raptor and the LTR 450 are completely different quads. The raptor is bigger and has much more torque, but you have to shift it quite a bit lower than the LTR 450. The LTR 450 is much lighter and revs to the moon with power all the way to the top. The Raptor is much more comfortable and has a softer suspension, where the LTR 450 is more set up for racing and is quite a bit stiffer. As far as the polaris goes I would just get the KTM if that is what you are looking for. They aren't that fast, however, for a 525, but the KTM version has some pretty cool options, but you will pay for it! As far as the YFZ 450 goes its a good all around quad. It dosn't really excell in any of the areas of racing, for instance, Motocross, or crosscountry, but it does well in both. It's a good dune quad. My recomendation however is the LTR 450. Not that I'm biast, but I looked all of them before I got mine. The LTR is fuel injected which saves quite a bit of headache IMO. The Kawasaki 450 R is a turd and pretty much a waste of time so don't even look at it! The other recomendation would be the BRP DS 450. Really cool quad!