Hi, I currently have an 80-200 f2.8, but it's too big for certain forms of travel. I'm looking for a compact zoom lens for travel purposes. I have a Sigma 70-300mm f4-5.6 APO Super that I bought as my 1st long lens before moving up to better lenses. I'm also considering the Nikon 70-210mm f4-5.6D lens, but not the Nikon 70-300mm f4-5.6D ED lens. Based on various internet sources I have noted the following: 1. Photodo.com has rated the 70-210mm sharper than the both the Sigma and Nikon 70-300mm. I think both the Sigma and the Nikon are rated fairly equally, although the Nikon has less distortion. 2. Lens survey website - http://www.photozone.de/2Equipment/lsurveyNikkor.htm - generally backs the results obtained by the photodo.com site. However, the rating for the Sigma 70-300mm differs between the two. Photodo rates the DL Super version higher than the original version of the APO (non- Super version) while this site rates the APO super very poorly vs the non-Super APO. 3. The opinions expressed about the Nikon 70-210mm f4-5.6D vary widely. 4. There is even more variance in the opinions for the Nikon 70-210mm f4. 5. I've noted good opinions about 75-300mm, but it is not compact enough. 6. The 75-150 Series E is a great lens, but it's manual focus and I want the extra zoom range. Based on these observations I don't feel the Nikon 70-300mm is sufficiently superior to the Sigma. If anything the ED designation may just be a marketing ploy, especially if the internet rumours are true that Tamron builds the lens for Nikon. The Nikon 70-210mm appears to be superior, but is it significantly superior or just marginally so? If it's just marginally superior than it may not be worth the trouble of getting one. Any insight would be appreciated.