Your 300/5.6 MF is not the same. The manual 300/2.8 is all white, stellar, but a tank. The 300 AF is also all white, f4.5 lens and phenomenal performer, being laser sharp even wide open. The 105-210 seems hit or miss. Most I have seen are acceptably sharp stopped down a stop or two, though a buddy has one that is quite good wide open --- but not as good as my 210 f4 AF prime, which is another lens that's a laser wide open...
Hope this helps,