I still like it, but my partner laughed all the way through it!

Rating: 8/10 (16 April 2015)

That summary may be the best way to review The Exorcist in a modern context, as its effectiveness is possibly dependent on the demographic of the viewer.
I first saw this in the late-90's shortly after reading the book. Both mediums shocked me, and I enjoyed them thoroughly! Rating it before the recent rewatch based on memory I'd be giving it a 9. As it is the film's dropped to an 8 because some of the narrative jumps felt clumsy, and the addition of cheesy scary-demon faces really dampened the feeling of dread.
I think The Exorcist Director's Cut I just saw (as opposed to the original cut I watched all those years ago) suffers from the same problem as Blade Runner's Final Cut, in that scenes are added which don't flow well with the narrative. Ridley Scott's film also lost a point because of this. Add the tedious experience of Paranormal Activity's extended cuts (over the thrillingly-paced original edits) and I'm beginning to lose faith that Director's/Extended/Final cuts are in any way a good idea to watch a movie.
Still, an 8/10 is in my book a very good film, and this it remains. Linda Blair is brilliant in the role, and props to the FX make-up: it looks awful (in a good way!). While the ageless Ellen Burstyn is competent in the role of concerned mother, it's the two priests who almost steal the show, especially near the dramatic end.
But people watch The Exorcist to check out the demonic possession highlights, and I for one was still shock&awed by them, tho' the big caveat is my younger partner was just laughing her ass off at these scenes. We both enjoy the subtle chills of Paranormal Activity, alas it seems 70's horror driven by make-up FX seems to be too silly for her. Suffice to say rewatching old favourites like The Omen is off the cards for now.
Conclusion: highly-recommended for almost anyone interested in classic horror, but avoid the Director's Cut. Some of you may find the film too daft to be taken seriously.