I was in the market last year and was in the same dilemma as you. My sled at the time was a 02 600 MXZ and I wanted the new chasis and also a different motor if I was spending the $. I was able to test ride the 09 600ETEC with a local dealer and much to my surprise, I had an issue with the ETEC. I did not like the low end. Now, the mid-range was awesome but when trail riding in the woods I like the snappy response as my 02 600 had. So, the dealer had a left over 08 800r and as much as I didn't want the bigger motor the salesman guarantee'd me it would be snappy like my 600. And I have to tell you it is! It's got good low end for me and by far has a TON of mid and high! The mileage is better than I thought and that I put in 1/2 to 1 gallon less of fuel than my wife's 02 600 when we fill up. I know the ETEC's are better yet on fuel and oil but if you like having some extra horses under you then I'd go with the 800r or 800ETEC. I do want the 800ETEC one day for the same reasons as others have stated (smoke, fuel, oil etc...). Hopefully I'll get to test ride it first and that I'll like what I see.... Just my .02.