I previously used the conti 4000's and converted to these for my go to race tires for the past two years. This with a latex tube is a wonderful smooth ride and extremely fast. I've had my best bike splits in IM distance and HIM distance races.
I like the 4000 S II 700C tires well enough that they're the only ones I buy. I bought two on sale at half price to keep in reserve for when the others wear out-eventually. The price was too good to pass up on tires I prefer.
These are my go to tire. Love the 4000s which just retired and have the new 5000s. The 4000s sidewalls has a tendency to blow after so many miles though. These 4 season have good flat protection, good roll and great grip. Rode 4000s and dura skin for years. These are all I ride now. I put on 10000 miles or more a year between commuting and weekend rides and good wheel sets, tires and saddle make all the difference.
Just purchased these in April - 2nd set on my Trek Emonda SL6 w Aeolus 5s - I purchased the reflective tires this round - they are awesome at making you even more visible & my first ride out, I picked up a carpenter's finishing staple. No tube puncture or anything! I highly recommend these. I'll probably upgrade to the 5000s on the next round.