I have the 870Q and recently bought the walking foot. Over 100.00. Ouch! Works good. The only thing I don't like is that there is no 1/4" marking on it. You need to use the single hole clip on foot and then "eye ball" along a notch. Other than it being expensive I liked it. There are many feet to try out. If you live where there is a dealer selling Viking go to the store and try the feet before buying. Ours will let you do that. I finally bought the piping foot and cannot believe how easy it is to make and put piping on. Why oh Why did I wait so long. Also recently bought the gathering foot. WOW! Love it!