Some lenses are considered as a must have. This is the case for Sony DSLR users with the Minolta 70-210 f/4.0 also called "beercan" considering it's shape. There is a reel hype on this zoom. Fortunately it is widely available on the after market and this availablity prevent the prices to raise to much.
I purchased my beercan at the same time with the M42 Jupiter 21M to get a 200mm f/4.0 for candid portraitures.
I was expecting the hyped zoom (I paid 140€ for it) to be as good as the old Russian prime (I paid 40€ for the M42 Jupiter 21M)
The Minolta AF 70-210 Beercan is a long (internal zooming) and heavy lens (700g). But considering it's interesting constant f/4.0 aperture it is not so huge. A f/2.8 70-200mm would be 2X heavier.
Without, and with the hood mounted reverted. The hood can be difficult to find if not provided with the zoom. And it is usefull to prevent flare.
The buid quality is representative of the beercan generation i.e. excellent. It is built like a self defense weapon (full metal and glass built).
The zoom ring is fluid. This is really a beautifull object.
Maybe the hype on this zoom is partially due to this point. But the beercan has other qualities.
The autofocus is noisy and can hunt in low light conditions. But in normal conditions it is accurate and fast enough.
When mounted on a body like the Sony Alpha 700, the beercan is less balanced than a smaller lens like the Tamron 17-50 due to his lenght.
When you purchase such an old zoom, you must be carefull with badly repaired copies (misaligned lenses), fungus, scratches. Some have been intensively used.
The beercan is not the perfect zoom for indoor shooting due to it's slow AF in low light conditions.
This is a versatile lens for outdoor portraiture because it produce a beautifull soft bokeh, with Minolta typical saturated colors.
The 1100mm minimum focus distance is very helpfull and is a great performance sor such an old zoom.
I would rate the image quality of this legendary zoom slightly under the Minota AF 35-105 f/3.5-4.5 "old"
I also prefer the big beercan, because of the better range and a slightly better image quality.
But make your own opinion having a look to :
this lens compared with other famous minolta zoom and M42 :
match @85mm with Jupiter 9, D kit tele-zoom, Minolta 75-300 Big Beercan, Minolta 35-105, Minolta 28-105
match @135 with Jupiter 37A, D kit tele-zoom, Minolta 75-300 Big Beercan, Minolta 135 AF f/2.8
match @200 with Jupier 21M, D kit tele-zoom, Minolta 75-300 Big Beercan