Here's a ghetto unboxing vid of me installing 50A O-Rings on my TKL MJ1 with browns:
[video=youtube;QzcahNJ-fz0]http://www.youtube.com/watch?v=QzcahNJ-fz0&t=3m[/video]
Jump to 3:03, the deep-link doesn't seem to be working.
Don't mind the horrible video quality.
Personally, I love the feel of the O-Rings. They've quieted my keyboard down a substantial bit as well as adjusting the feel of my keyboard to my liking. The board feels a bit more "bouncy" and responsive. I'm not sure if it was me getting used to my keyboard or the installation of the O-Rings, but my WPM has shot up from 90 to 115 a week after putting them on. For me, they were well worth the small investment. For my wife, they are *EXTREMELY* worth the investment. The silencing that it does has made her nights much more enjoyable.
I'm looking at getting some 40A O-Rings in the near future for a comparison. The 50A O-Rings are working well for me, YMMV.