I bought F4, but only tend to run at approx 1200RPM, as I want quite operation, rather then performance. I had never used slim before, but if you look at most CPU/GPU AIO's, they use slim rads, so the performance is good enough.
No doubt, the PE's are the better performers, which is to be expected. I have also read that the SE are not the best slim rad, but again, my use case was not performance. I am happy with EK products, so stuck to what I knew.
My build is nearly the same as yours - 4790 and a MSI ref R2 290 (stock). I got approx 40 degree load with PE and all SP. I have settled on approx 50 degree load now, but the F4 has cut down the noise.