Summary:
I don't think you could buy a better trimmer. It is a runner and I have had no problems.

Strengths:
This thing is unstoppable. It is a great trimmer

Weaknesses:
None so far

Summary:
easy to use awsome power

Strengths:
power easy to start

Weaknesses:
none

Summary:
Bit sceptical when purchased as bought a Honda 4stroke and wasn't impressed but it's kept up with stihls practise of producing good tools. Surprised nobodies come out with a kevlar shaft to help keep the weight down.

Strengths:
Easy starter, good fuel economy, less emissions. I give it a full minute to warm up then it gives me full power for as long as i want

Weaknesses:
only the exhaust outlet, the fs 85 that it replaced had a rear discharge exhaust, the fs90 is side discharge so have to hold the machine lower when working right to left on steep banks so i dont burn my arm or breath in the exhaust fumes

Summary:
The reviews on this motor have been showing these problems, but I thought I would try one. My comments to Stihl---"This one needs to go back for more R&D !! Maybe mine was a fluke, but have read of others also !! I feel sure the folks at Stihl will investigate problem !! Good Luck !!

Strengths:
Sarted easy, ran quiet, felt good for about 4 hours, then "DIED"

Weaknesses:
Obviously, this is not the Stihl I know and love to operate !! Motor rattled,shook and siezed !! Mix was Shell 89 octane-Stihl Ultra oil at 50:1 ratio !!

Summary:
A previous post of the FS90 Stihl problem, was found to be a missing cir-clip on piston--which allowed the motor to self-distruct. I feel sure,now, knowing Stihl's reputation this was a unfortunate assembly error. I selected to take a FS80 as a replacement.Still feel the Stihl is the best one out there !!

Strengths:
See previous post !!

Weaknesses:
See previous post !!