I have 5, 301's and no 500 so there's my answer:> I do own a 401 which is the same machine inside as the 500 and I guess the important, distinguishing question would be what do you need it to do? Piecing and FMQ only then for sure the 301. If you need other stitches, then the 500. The 400 and 500 series are not good FMQ machines, so take that into consideration. I use my 401 and like it, but since I FMQ a lot, I prefer my 301's. Black 301's are much harder to find than the mocha ones.