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.
I have been using GP4000 tires since their introduction, for a total of somewhere in excess of 25000 miles. They are tough, light, and terrific at cornering in all road conditions. I generally get about 3000 miles out of a set of these tires before the wear dimples disappear. This riding over largely chipseal roads. The only problem with these tires has been pointed out by a few reviewers, has to do with the sidewalls being somewhat fragile. I have only had to throw away one tire due to a sidewall puncture. It was upsetting due to it being a brand new tire, but I doubt that any tire would have survived that particular road hazard. I consider these to be about the toughest tire out there. I will continue to use them as long as they are available.