well let me just say that i am partial to the triple's but the efi on the A/C is also a very handy option. The triples usually run smoother than the twins which means less vibration. Triples are usually faster than twins when you get into the upper RPM's and twins usually have more torque off the line. I guess what i would look at is the mileadge and see what condition the tracks are in. And also see if you can determine how hard each sled was ridden. If it looks like it has been ridden very hard its entire life the stay away from it, if it looks to be in good condition ask if you can check compression on the cylinders. If these all check out ok its time to decide on which brand you prefer or which one looks better to you. Personally i would say go for the Polaris, but like i said im a "little" partial.