VERY good, love it. Bought it for my CBR years ago and it still fits the FZ perfect. It's a stretchy spandex material. Has holes for the mirrors and little loops to stretch it down to the foot pegs. Hasn't ripped, folds up real small to be put in a little carrying bag.
I bought one of these last year at Cycle Gear to store mine in the garage for winter. The price was right and I don't consider keeping dust off of it a very hard job.
So far no problems. It looks like it'd take some outdoor elements pretty well, but it's more of a lightweight cover than rain guard so if the idea is to let it sit in the elements I'd probably get something heavier duty to keep off the downpours.
It packs away into an acceptably sized bag though and, my favorite part, doesn't have any tight areas where abrasion is going to eventually leave marks or scratch up plastic pieces.
If you're keeping it outside just keep an eye on the moisture build up inside the cover. I had a cheap cover before buy the dowco and i would take it off in the morning and my bike would be drenched.
The venting on the DOWCO was much better and I no longer have that problem. One thing I saw on the dowco was that water would build up by the handlebars if you have bar ends. I switched back to regular Rizoma mirrors and no longer have that issue (it wasn't an issue per se as the cover didnt let any of the water seep through but on my last one it did).
If you have bar ends regardless of what cover you have - you may want to prop up a stick with some duct tape on the end of it so it doesnt scratch anything and prevents water from building up by your bars.