I bought one for my Janome 6600 and so far have used it to embellish a couple of bags - one of them is in my photo album. It's important to reinforce the central point and also to find the exact center of the circle but, apart from that, it's very easy to use. I bought mine while on holiday in Sante Fe after looking at it for ages in my more local shop. The tipping point for me to part with the $70 was the exceptional work on display - they had made scalloped edges for a silk jacket with five or six circles of embroidery - all perfect. It's also useful for making curves - too big circles - that go off the edge of the fabric. I just played with mine - it's fun.