The anti-vibration capacity of the 395 is a light year ahead of the 660. The carburetor is completely vibration-isolated and that helps with longevity.
I sold my 660 and 066 and now I have a 394 and a 395.
I've never worked on a 395, so I'm glad to hear all the positives about it. For some reason, I've never considered it before, and haven't paid a lot of attention to it. Honestly, I don't know what else I'd consider besides a new MS660 of 395XP.