I've always craved one, but I spent some money on a pig in a poke..bought on an Ebay auction a deck, and two grass catchers, and all attachment linkages, etc for a B series instead of a BX. Silly me. I still need to sell all that stuff. I have quit crying about it, since I only paid $400 bucks, and SOME parts could be used on my BX deck if needed.
In the end, I wound up buying a JD rider with grass catcher new, but at a great price, well less than the BX catcher would cost, so I use the rider now, and use the BX only for tractor work. If the JD dies, or lets me down, I can put my BX deck back on and mow. My buddies think it could be better for the yard, since the JD is lighter, so may not compress my soil as bad, but no actual calculations were done to prove that.
On problem this settled is that the JD fits in my garage no problem, but my tractor could not fit in its building with the bagger on anyway.