Well I don't have any experience with that lens, my main lens is a Tamron 28-105mm f2.8 It has been a very sharp, clear lens with good contrast. Tamron is making very good glass (in some cases maybe better than Nikon).
I had one and sold it. I wanted to use the lens for sports photography, but the contrast above 150mm or so is poor, focus speed wasn't fast enough, and the lens is slow.
With an F100 (I don't have a D100), there was very noticable light falloff toward the edges in photos of ski racers (where there is a lot of white, which exacerbates this problem). With the smaller D100 image size, this may be less of a problem. This was the last straw and I sold the lens and replaced it with an 80-200mm AF-S, which, not surprisingly, is far superior.
Having said all that, the lens is great for travel photography if you value convenience over image quality. I now carry an 18-35 f3.5-4.5D and 35-70 f2.8D, along with the 80-200 (only when needed), so there is a big weight difference, but, for me, the improved image quality is worth it.
I use a Tamron 28-300 with my D100 ( I do have other lenses as well).
In contradiction to what a lot of people say, I think it's a great lens. Because of the smalle angle of view on the D100 I don't have any problems with softness around the edges or similar problems. I most say though that the AF performance in low light is cr*p. This is not a lens for the sports photographer!
I wanted a small and compact lens that I could use as a "every day lens" and for my travels where I don't want to cary a 40 ibs camera bag.
Tamron has already showed that the "old" problems with long zooms is a part of the history, the 28-300 is their latest statement to that.
I can recomend this to any amature photographer who's on a budget ( like me).
I've used bronica lenses for many years, the newer bronica lenses are manufactured by tamron, obviuosly a few years back tamron merged with bronica and introduced newer optical technologies to bronica. I don't knock the quality of tamron, I've never used a tamron lens but since the D100's 1.5x focal length factor most after-market zooms light fall off is really not a significant issue. I'd say the main features to look for in a zoom for a dslr are angle of view, speed (aperture), focus speed, size/weight, minimum focus. I currently own a nikon 18-35 af-d 3.5-4.5, and it's a good enough zoom for what I shoot. Everything else I shoot is with a 50mm & 85mm, both 1.8 aperture. The tamron lens sports low dispersion and anamalous dispersion glass, and has 19" minimum focusing, F6.3 for a 300mm is a bit slow but not horrible. I'd say it's not a bad lens.... 28-300 in D100 language= 42-450mm, not too shabby, heavy at 14.8 oz...
I agree with Karl but would not go as far as Langwood. I have been using the lens on my N80 & D100 for the past year. It's a good quality lens for general use, do check out Sigma and Tamron new versions of the 28-300 and 28-200.
The lens works smoothly on both bodies, AF does slow down with increased zoom and lower light levels. I have used this lens on the recent Moab 2002 trip--in bright desert sun, sunrise, sunset and after sunset. From wideangle to full tele, the images, film and digital are crisp; the small amount of vignetting and softness that appears on full frame film does not appear on the restricted view of the D100. You are using the best part of the optical image with the D100. Enjoy the latest versions of this lens now, then as your needs become more selective go for a used Nikon 80-200-2.8, about $600 street. Add a used Nikon 28-70-2.8 alater nd you are optically set for life, remember it is the creation of the pictures that count, dont get bogged down with the tools.