Hi Salectric, I have not tried the newest KLE plugs but from my experience with older models I think they are comparable in sound quality to the Furutechs that go for the $150 range, as I use on my D2, D3 and DD cables... but I doubt they will be close to the $400/set WBTs and Furutech CF series RCA plugs. The only reason I am not giving the new ones a chance is simply build quality, I'm not super happy with all the plastic... that's one of the reasons I went to WBT 0102 on my D4s. Also, there is enough variance in the diameter of RCA jacks that having a locking RCA plug that fits well on any RCA jack without the potential for being too loose or too tight is a better way to go.
That said, the KLEs are a good choice for DIYers looking a good value and who will be careful with their gear.