I have a Baby Lock Imagine 4 thread serger that's probably a bout 15 yrs. old. Personally, I wouldn't want anything but a Baby Lock serger, mainly because of it's ease of threading. Previously I had a Singer but it was a nightmare to thread. Not familiar with the BL3-407, but it should be good. If I were to get another one, I'd want one with a cover stitch. Is the one you are considering in good working order? And a reasonable price?