This is late, but here we go... It's my understanding that the Stihl 290, 310, 390 are the same basic unit, but bored out differently - that they all weigh the same, and all come with the same manual seem to indicate this as well. If this is the case, then the 390 is going to be a decent saw, but not one of Stihl's best by any means. The 290 was introduced to get guys (like me) who want a reliable, brand name saw, with enough power to handle dirty jobs - the "Farm Boss". As such, it has plastic where more expensive saws might have an alloy, but still has things like a compensating carb and winter modes etc. More features for less money, and that means quality has to drop somewhere, but if you don't need a "professional" saw on a daily basis, then these units seem like pretty good value, especially if you can get em on sale.
