I added o-rings to my mx browns, the "Red 40A-L (0.2mm Reduction)" ones.
...I kind of hate it.
I'm going to try them for a week to see if I get used to it but I doubt I will. Only the spacebar feels better.
I use the same ones on browns. My initial reaction was the same, but in time I started to like them. Now, I prefer to have them on.
Make sure to give each key a few good pushes before typing to make sure all the o-rings are in the proper place. If not, it will feel very odd. To me, the feel of the mechanical switch remains the same. It is just the feeling when bottoming out that changes. It is a little softer, and you bottom out faster. The former I am not so sure about whether I like it. The latter I have come to appreciate.
Keep in mind that with the muscle memory you built up with they keyboard, any change will probably feel worse at first.