I inquired about opinions on the topre "silent" models a while back. The response that was given to me was that the dampening rings wear after a few months, so some people felt that the key feel was uneven due to some keys being used more than others. I could understand a similar issue occurring with these things, but I think everyone needs to just assume this will be the case going into a mod like this. I don't think they will need to be replaced, but there are always going to be people who feel that they "need" to.
I am excited to try them. I want add them to a board and go use it in a library and see how quiet it is.