Hurricane Wilma uprooted several trees in my yard. The biggest is about 16"in diameter. Tired of the junk sold at the big depot stores. Have decided to get either the MS250 or MS270. I will probably be moving to NC or TN in the next few years where I'll cut trees on my property for firewood (not for heating). I'm not looking to make money with this saw but do want a good saw that will last a long time and save me time and energy. One dealer says the 520 is fine and the 270 is over kill, the other dealer says the 270 cuts faster and meets my future needs better, but admits the 520 would also do good job. The difference in price is $80. Don't know if the 'Exclusive tool-less Quick Chain Adjuster' on the 270 is a gimmick or a good idea. Is it worth the extra $80 for the QCA, a little extra hp and the anti-vibration system or am I just being up-sold to something I don't need?