Did you see the threads in the Attachments forum? The most recent is pinned to the top of the Topics list, and it has links to previous discussions in the first post.
I did look back through the discussions, and found this post from a B7800 owner, but I recommend reading through all the posts if you're unsure about purchasing a set. I bought a set for my L345, and they work fine for me.
I've had one on my 7800 for about a year now. Well worth the $200. Especially if you use a post hole auger. I don't switch implements that often, but I no longer curse when I do.
I've been using a set on my B7800 for at least a year. Works on everthing except my backhoe. There may be better (more expensive) systems, but it has saved me a lot of time and busted knuckles.
It does move implements back 3 or 4 inches which for me has not been a problem. The 800lb chipper got quite a bit heavier sitting back that much further, but works fine.