My new build is in an h440. It is a really, really hot case. I use an h100i with a 4770k and the temps are about 5 degrees hotter at idle and 10 degrees hotter at load than when I had the rig on my test bench. I have mounted the rad at the top.
I have not tried at the front yet, I was thinking about it, but not yet, and it is not something you normally see - a front mounted AIO for a CPU. It can make the inside of your case much hotter, but it does give the benefit of supplying the rad with fresh, cool air from outside, rather than warmish air from inside the case. It also gives lots of space for push pull configs. Just make sure you put fans at the top of the case too, so that you have enough exhale.
I would suggest trying both, and checking the temps whilst running p95 for a bit, see which is more favorable. You can keep the block attatched to the cpu whilst you move the rad about. It does look much better to have the pipes going up, instead of stretched along to the front though... just saying