I wanted to replace my old aging FS85 straight shaft it has carburator problems and its tired. It is close to 12 years old I bought it when I was in the grass cutting business which I no longer do. I still cut grass for my parents its all weed wacker work because its not flat and its not a lawn. Anyhow I was humming and hawing about fixing the FS85 but decided its time for a new machine so I bought FS110 with the new 4 mix engine. I'am happy with it so far. The 4 stroke has more power it is quieter and it isn't as heavy as I thought it would be. It does get better fuel economy over the 85. I went to the rental shop which is the local Stihl dealer looking for prices and they had 110 with the bike handles which is what I wanted it was on sale for 589.00 dollars Canadian. Took it home put it together and started cutting. The 110 cuts like not tommorow with the 25-2 trim head it walks through the heavy wet grass like ease the 85 would bog. I won't put a brush knife on the new machine for awhile. Hope this machine goes for 12 years like the 85. The 110 won't see as much abuse as the 85 seen doing commercial mowing. I'am glad I went with the 110 over the FS90 I looked at the spec's and the difference in price was 70 dollars. The 110 has 31.4 cc engine over the 28.8 cc engine the FS85 has a 25cc engine. I will prolly get the FS85 fixed and sell it to my brother he needs a trimmer over at his place. It will do what he wants to do for me the old machine is a little too tired for cutting 3-4 hours at a time. Not sure what a 12 year old 1 owner trimmer would be worth nobody else has ever used it but me and I kept it tuned up it still has the original carburator its never been touched. Since new I only used Stihl oil and premium grade gas. Hate to see the FS85 go its been a good trimmer for me it was my first new piece of equipment when I started in the grass cutting business.