I have one of those (the manual one in the video, not the electric one). It helps but it's not as good as a new blade. It works best if you sharpen as soon as you notice the blade is getting dull - I haven't had much luck putting a new edge on blade that's REALLY dull. And if you have a nick it won't do anything for that. I think it's worth it as long as you don't have really high expectations for it (and if you can pick it up on sale - I think Connecting Threads has it on sale right now, actually). It will make your blades last a good bit longer (maybe even 2 or 3 times as long) but you'll still need to buy new blades on occasion.