Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Would you use this lens for portraiture?  Is it as good as the 85mm fixed lens?
Document: light weight and takes nice pictures. bought it to use inside but takes all around good picc. i would recomend this lens
I got this lens for it's resolution. It does not disappoint. I bought it also for a possible full frame upgrade and for the VR. My sample has a problem though. Unless you use it on a rather large DX camera or an FX the zoom ring is very stiff. This may loosen over time but it seems too tight to start compared with other mid range zooms I own. Called my vendor and he said this tightness was a good thing and it would relax over time.
I didn't buy this lens with my Nikon D600, because all kit lenses suck, right? Wrong. I bought this lens separately because I read the rave reviews. I wish I'd gotten the D600 kit with this lens included and saved money.The 24-85mm VR is edge-to-edge sharp -- it seems as good as a fixed-focal length lense in that regard -- and the VR works as well or better than any I've used.
I would highly recommend this nice little lens for a daily use for any FX format Nikon. When use it on my D7000 it a acts roughly as a 35-125mm lens.
If Nikon plans to use this in a kit with a future FX SLR, it would be a great choice for an all-purpose walk around lens. OTOH, if you are using a D800 with the mirror up, trying to get that last little bit of detail, this lens should be fine but it won't get everything the D800 is capable of capturing.FYI, except for the caps, it's made in China and yes, the lens mount is metal.
Frankly, the older 28-105mm seems a better lens in every way, but for a lack of direct software plugin support on DxO. Were the lens module available for software image automation, I like others would be off loading this lens in favor of the 15 year old lens.ADDENDUMThe more I use this lens, the less I like it. IQ just doesn't measure up to the standard for an average Nikkor lens.
This lens lacks the capabilities of an older tech 28-105mm Nikkor, and just cannot seem to match for color rendition. I would recommend saving the $350 on the 24-85mm, and get the used 28-105 for around $150
While both the 24-85mm(FX) and the 18-300(DX) together. Each lens is designed for optimum operation on a full frame and 4:3 ratio sensor. Buying the 24-85 and putting it on DX does not make much sense because you would have the equivalent of a 50-170mm zoom. Nikon makes better lens options than this.
I bought a low-mileage D700 two months ago and was dissatisfied with the 24-120mm/3.5-5.6 Nikon lens that was on it. After looking at four different lens reviews, and asking two photographers who owned the 24-85mm/3.5-4.5 Nikon lens, I felt that it would be a sharper lens, albeit not have the same long reach.
:)A perfect economical pairing to 24-85mm VR lens would be Nikon's 70-300mm VR II as it is Nikon's best 5 Star variable aperature telephoto lens.The 24-85mm lens here does have it's fair share of distortion at some of it's aperatures and on my D-600 with "Auto-Distortion Control" turned on by and large you won't notice a bit of it.The color and contrast of the Nikon 24-85mm VR lens is amazing and gives photos close to Pro quality everytime.
Answer: I would suggest you do some study on lenses and focal lengths in general. I have this lens and primes and longer telephoto....it all depends on what you are trying to achieve.  Questions like this tend to get responses from people who don't know what they are talking about, but are repeating what they read from someone else who read it from yet another, etc. etc.  By "portrait" do you mean  a lens that does not distort facial features?  Then you want something that you can get further away from your subject.  85mm is fine for that, and zoom or prime doesn't matter if both are good lenses.  Blurring of background?  Sure, a wider aperture will do that --  but even better is a longer lens and a greater shooting distance.  "Primes are sharper" is not necessarily true anymore, and the widest aperture isn't where a lens performs at its best anyway.  This is a fantastic lens - and I use it for portraits quite a bit...until I want an effect it doesn't give, and then I use another lens.  Study up on lenses generally, and you'll see my point.