I have been saying since I first threw a leg over an etec throw that in a polaris chasis and boom best sled hands down. Now think about the 850 etec turbo in a axys or matryx and all I can say is take my money! But as far as naturally aspirated goes the Polaris engines since the axys came out have been solid. This was my first winter back on Polaris after 7 years on doo and I never had one issue with 2500 km and am very impressed and feel right back at home on the poo!