Honestly, I have no image stabilizer no miracles at 300mm expected but the opposite is the case even handheld shots are possible without any problems and mostly sharp.
Use the Tele to my new D60 and have used it one week at the D40 and am completely convinced (at both DSLRŽS).
Quality workmanship and compact dimensions are only two of many purchase arguments, previously had the Tamron can test with the same push for a day by an acquaintance and had the Sigma clearly (thankfully) made a better choice.
My Conclusion: For this price an absolute must !!