October 2010
I have updated this post a little more and have since acquired a Kiron 105mm, Lester A. Dine 105mm, and this Vivitar lens in Nikon F (AI) mount. I previously was using an MD mount via an optic-less adapter. Also, after much more exploration into the Series 1 lenses, I must say in terms of design while I originally stated this was the best in terms of design ever, I must redact that statement as I have come across some beautiful pieces that now have me "on the fence".
Recommendations
This is a great lens. But if given the choice between this and the Kiron/Dine, in terms of performance, I would have to point you to the Kiron/Dine. Both my Vivitar copies rendered softer macro images than these other models. And if you're really looking for sharpness and performance from a macro, just get the Tokina 90mm f/2.5 and forget about the rest of them (unless you need 1:1 without messy adapters). Want the best looking of the group? Then by all means, get the Vivitar!
In my opinion, the Vivitar 105mm is one of the smoothest, most aesthetic lenses ever designed. Definitely one of my all-time favorites. I have been known, at times, to select/purchase lenses based solely on their aesthetics, only later hoping to discover the lens has the accompanying optical merit. Sort of the wrong approach when thinking about trying to achieve superior output. This was not, however, one of those purchases. I actually did my homework (for once!) and spent some time looking for a good sample of this lens to come along. Also looking for the right price.
Cat's outta the bag now. This lens is awesome. Often referred to as a cult classic, look for a 105mm Dine, Kiron, or Vivitar such as this one and you will be buying the same optical formula in a different outer package so to speak. That's not to say, however all these lenses perform the same. As of October 2010 prices seem to be on a lower end for what I have seen, perhaps due to the economic climate. 
Aesthetics/Cosmetics
I cannot say enough, this lens feels great in the hand. Focus is extremely smooth and the long-throw just makes for greater precision. The focus ring is a smooth, durable, foam-like rubber. Every edge of the fully metal construction appears precision cut. Upon closer inspection, you can see and even feel the tiny grain in the metal from the machining. I have always loved lathes and the way machined stock feels. The Kiron and Dine version of this lens both handle very similarly. I prefer the larger lip of the lens hood on the Vivitar 105 to the slimmer hood of the other variations. The Vivitar's hood also retracts and stays whereas the other 105 versions I have owned have had a little more play in them.
All versions of this lens appear to be multi-coated. I have not noticed much of a difference in contrast, flare control, or anything else optically in regards to this so I would say of those three, they should all be pretty solid. I have not used any of the other iterations which are a bit older and may have slightly more archaic coatings.
Specifications
Focal length: 105mm
Filter thread: 52mm
Min. Aperture: f/2.5
Max. Aperture: f/32
Angular field of view (diagonal): 24°
Elements/groups: 6/6
Min. focusing distance: 13.8" (35 cm)
Aperture blades: 8
Dimensions: 102mm x 72mm
Weight: 10.9 oz (656 g)
Specification info from Photodo.com
Performance
It's an oldie and thus is fully manual. I have seen numerous listings on eBay which cite old age and poor eyesight as the cause for the sale. Older folks are moving to auto-focus. While I still have my eye-site, when doing macro work, I always manual focus.
Along with the slick industrial design, this lens proves itself optically, a worthy opponent of the best macro lenses even today. It did not achieve cult status for no reason. It is sharp. Chromatic aberration occurs at f/2.5, is extremely minor at f/4, and effectively gone by f/5.6. After more use, I noticed some softness wide open. This normally wouldn't be an issue had it not been for Vivitar's Series 1 90mm f/2.5 and Tokina's later 90mm sibling which demonstrated amazing sharpness wide open. In fact, even Kiron's own 105mm and the Lester A. Dine dental version perform superior to Vivitar's 105mm wide open. See a comparison here. Michael McBroom (Blogger and reader of this blog) commented, "Perhaps Kiron kept the best of them back for their own brand name?" I think this is a great hypothesis!
Reportedly, the Vivitar Series 1 105mm does not perform very well at longer distances. I never did get around to checking this. I can't say I really ever looked to using this lens for anything but macro work.
Wrap-up
This is a great macro lens save for minor chromatic aberration at early apertures. I have not used it for portraits, but if spending the money, from what I can tell (and what I hope to test when I have more money) better portrait/macro lenses exist. I'm sure it would perform beautifully in its own right though, especially given it is a hair soft wide open. For use near infinity, apparently this lens is nothing special but I never tested this. Physically, the lens is gorgeous. I would pick one up just to put it in a display (but I would get more pleasure out of using it!). Its optical performance and design combined with its shortcomings certainly explain the "cult" status. While for some it is a capable, solid, marvel of industrial design. A true personification of the old maxim, "they don't make 'em like they used to". Others may find it heavy, klunky, inconvenient and overall obsolete.If you find one for a good price (Especially in a Nikon F mount. Other mounts are not worth as much since they are not as compatible with current DSLRs) I would recommend picking it up without a second though. You will most likely be able to give it a try and at worst resell it for a full return on your money.
