I have a Janome serger, and I've been happy with it. Ease of threading is pretty much the top thing I would look for, and the lower looper is the hardest one to thread. On mine, that has proven to be pretty easy( if you follow directions!!LOL) As to what features to look for, I think that will depend on what, and how much ,you plan to use it for.The rolled hem foot and differential feed is important, and a 3/4 thread. Personally, I use mine a lot, but mostly for straight seaming/finishing, I've never really tried to do most of the things they can be used for, the decorative type sewing. If that is of interesst to you, you will need to study serging books and even take some classes to get the most benefits.