I'm now looking I'm torn between the Echo CS 490 and the CS 590 TW. I'm going for an 18" bar more than likely. So, is one a home owner grade and one a Prosumer grade? I'm looking for a saw that will last me 15+ years. We had a John Deere saw years ago that would just go through the clutches every 6 months cutting Cedar. I hated it. Do they differ in terms of quality? Does the the 490 use a cheaper made clutch or motor? Echo claims both are made for pros. I talked to Echo and the lady claimed both saws offer a 1200-1500 service life on the motor and drive. True?