I just added a pair of CS 2.3 speakers to my collection and was pleasantly surprised. I've read that they need tons of power, but they seem to do fine with my Herron M1 150 wpc monoblocks.
I've been in love with my KEF Reference 1 speakers since I got them, but the Thiels do some things better. The Thiels have great imaging, soundstage, scale, and detail and a great midrange. I'm not ready to sell the KEFs yet, but the Thiels seem like they are going to give them a run for their money.
I have read numerous comments about them being "bright", which I am averse to, but I would not call them that. They do have a little "edge" when pushed to very loud listening levels, but many speakers do and that's not how I listen. I usually keep it around 65-75 db and they are fantastic in that range.
These are all first impressions with only a couple of hours of listening and no experimentation with setup. I set them up with almost no toe-in on the advice of the previous owner and that seemed to work great, but I plan to experiment.