This is my first post so please be gentle. I have been lurking here for quite a while and have learned a lot of new and great things! My old (late 70s) 031 Stihl is on they way out. I checked at the dealer and I am going with either a MS310 or MS390. There is a $120 price difference between the two. Does anyone have any feedback on which would be better? The 390 has slightly larger displacement and a decompression valve. Otherwise they are about the same, including weight. I plan on running the 20" bar it comes with. I am usually cutting wood several times a week. Any feedback would be appreciated.