zipper failure
Con:
I purchased this bag, along with a lawn mower, two seasons ago. The inboard zipper pulled past its "limit point", and would not re-link, after only one season. This third season looks to be the last legs for the other zipper, as I have been careful to the point of nuisance, in trying to prevent the seconds' failure.
The spreader/support bar, inside the bag, is also beginning to show through.
The stand-off bar post will strip its plastic hold with a small amount of pressure, so mowing close to any object on your right will require pulling the mower backwards from the left.
Pro:
It is very easy to get on and off, and only emptying twice on a 5000+ sq. ft. yard in a Cleveburg, OH suburb.

grass catcher - great time saver
Very easy to attatch to the mower; saves a lot of time not having to sweep the driveway and sidewalks. Also, cut grass doesn't dry out on and choke the lawn because it is collected as you mow. Thrilled with the purchase.

Useful attachment
The bag works, but the problem is the way it attach to the mower on the side, a little cunbersome, and also it makes the hole thing twice as wide, making it impossible to work the machine in tigh spaces.

Black & Decker Side Bag
Works well. Only drawback is that it's small. You will have to dump it many times, even for a small yard. Zipper gets caught quite easily.

Black and Decker is TopNotch
I really had my doubts about a side bag on an ELECTRIC mower?? Snaps on and off easily, Black and Decker has some great engineers, this is a perfect example of putting the consumer first. Four dollar gas is not problem for me with my GRASSHOG!