I use my PS3 for Netflix, Amazon Prime, etc. and it works great. I have no reason to think the PS4 will work less well at that. And so far it's only online gaming that requires PSN+ not Netflix, so (unlike Xbox) I have the option of watching Netflix without paying an extra $50/year.
X1 will finally have blu-ray, but I expect Sony's playback will be as good or better since they've been offering it since 2006. And I try not to use my 360 to watch DVDs because the image quality is not as good as on my PS3.
My PS3 netflix is stellar. The Prime is mediocre and has gotten worse over time. And the lack of HBO Go really irks me.