100%, the GP5000 seems to be correctly sized, the 4000 were always close to a size up.
Have used both and have went through two pairs of the 5000 so here is my opinion.
Puncture protection: GP4000S wins hands down, the 5000s has picked up numerous punctures whereas, with rare exception, the GP4000S did not puncture unless they were near end of life
Lifecycle; GP4000S again, at least twice if not three times as long out of them compared to the 5000s
Grip: 5000s wins hands down, I took corners in races at speeds I would have went off the course with the GP4000s. If your not an idiot risk taker, you won't notice but the 5000 have far superior grip, and this is with the knowledge that the 4000s were some of the best tyres I had ever used for grip.
Rolling resistance: I think the 5000s are lower but to be honest, it is such a small factor that it could be in my head, also with the sizing being different, it is hard to compare, the 5000 in 25s, are similar to the 4000 in 23s on most of my wheels.
Long story short they replaced a great all round tyre for racing with a really good racing tyre.
I am going to use up the sets I have for commuting and buy a fresh set for racing but I only expect to get the year out of them with just racing.