OPinions on 700x21c tires

For the most part I have used the 23c tires. For the last few months I have been using 25C tires, only because the wheels I purchased came with them. I went to the LBS today to get the Specialized Comp Turbo tires (23C) that I had on my old bike and loved,, to use in next weekends HIM. The LBS only had 1 in stock, but agreed to sell me 2 of the S Works version of the same tire for the price of the turbo comp tires.

The only thing is the S Works tire is a 21c, which I have never been on before.

Long story short, I'm looking for opinions on this size tire or better yet, if you have this tire (the S Works) I would love to hear your experience. My main concern is cornering and most importantly puncture resistance.

TIA