As the first poster said, it doesn't really do a great job of keeping dust off. I do use one constantly, but it is more for protection against errant knocks than dust. I keep a fan shaped artist's badger hair "blender brush" by my turntable to brush dust off. It's got a long handle and is easy to use to sweep dust out of the nooks and crannies.
VPI Dust Cover
Does anyone have any experience with the VPI "Budget" dust cover? I have a Scoutmaster with a Gingko plinth-top dust cover. My table sits on a wall mount (Target) about chest high, and I'm always worried when I put the cover back on that I'm going to hit the tonearm or cabling in back. The VPI cover looks a lot lighter and easier to slide on and off, but the section that goes over the tonearm also appears to be open in front and back, which makes me wonder just how much dust it can really keep off the tonearm and cartridge. Has anyone used one?