amsoil (like most others) is way overpriced due to a very good marketing campaign, Citgo sea an snow is just as good.(actually i think it has the same or a higher rating) There are guys on this board and others with tons and tons of trouble free miles using the citgo. both on stock and modded sleds.
I personally have over 10K on 3 sleds running it and find the valves to be a little cleaner than oem oil or amsoil. The less a person understands about oils and there rating systems, the more they are willing pay for oil. This topic gets beaten to death over and over on this board and every other site 3 times a year. and the genreal consensus usally ends up being this.
Use amsoil if you dont understand oils and there rating system and your mind set is geared to "it costs more so it must be better" OR run the citgo sea and snow if you do understand oils and the rating systems that are used and you like to save some money. As far as the hugo arguement that is up to you. If you want to buy american use the ams, If you dont care run the citgo. Not sure if the whole snowmobile industry boycotted citgo if it would even make tiny differance in hugo's profits (might hurt the refinery in texas though?)
Its up to you, you can either pay for a ton of marketing and get a good oil, or you can NOT pay for a ton of marketing and still get a good oil. Either way your sled will be just fine!