Here's my real world review of the Tamron 70-200 F2.8 Di VC USD. After I sold my Sony FE 70-200mm F4 G OSS lens to upgrade to this lens, I have compiled some user notes aggregated from my real world experiences.
Lets start by breaking down the full name of the lens:
SP - Super Performance (Sounds ambitious, though, I suppose its true)
Di - Digitally Integrated (??????)
VC - Vibration Compensation
USD - Ultra Silent Drive
Ultra Silent, or Ultra Loud?
The lens is not silent at all. The lens is very audible when focusing, one of the loudest focusing lenses I have ever used. Does this affect image quality? Is the focusing slow per say? Definitely not. But the USD designation is ironic to say the least.
Infuriating Tripod Collar
On my previous Sony F4 version of this lens, the tripod collar required maybe one rotation of the knob to fix the collar to the lens. The same is true of the Nikon and Sigma versions of the 70-200 F2.8. However, the Tamron version is a simple screw on tripod collar, which takes maybe 5 rotations of the knob. If you want to take off or put on the tripod collar quickly, this lens will definitely slow you down. It also feels flimsy in comparison the Sony mirrorless version as well. Additionally, it's more difficult to attach as well, as the collar isn't "funnelled" into the groove as it is on other lenses. Overall, although not a big deal to many, the tripod collar seems like a afterthought.
The Nikon 70-200 splits the tripod collar into two parts. The ring wrapping around the lens, and the part where your tripod plate attaches to. This has been found to be a more durable design, absorbing impact if your camera happened to fall off a tripod. I hope Tamron incorporates these improvements into this lenses successor.
In terms of build quality, the lens is probably what I was expecting for the price. Many lay into the name brand lens manufactures for being overpriced. Though, the name brand lenses are generally in my experience far better built. Similar to the Tamron SP 24-70mm F2.8 Di VC USD, the zoom ring feels like it gives way slightly when you press on it. The exception in my experience are the Sigma Art lenses, which are one of the best built lenses I have seen. Happily, the lens has a weather sealing gasket around the mount.
Ergonomically, I dislike how the focus ring is further towards the back of the lens, and the zoom ring is towards the front. I constantly find myself accidentally adjusting focus while zooming. The Sony, Nikon and Canon 70-200 lenses arrange the focus ring at the front, with the zoom ring towards the back.
Optical Performance & Focusing
The lens has similar if not better optical performance to the name brand Nikon and Canon lenses. However, the Canon is the only one that doesn't exhibit severe focus breathing at close distances. This can come into play when taking tight headshots, as the Nikon and Tamron have a similar field of view at 200mm as the Canon at around 150mm. This can be remedied by extension tubes. The vibration compensation is great to have on a telephoto lens, and it works great.
Sharpness at Varying Apertures (Center of Frame)
The following is some data from my independent testing, using automated software. Quality of focus denotes sharpness.
The graphs illustrate that the Tamron 70-200 is sharpest at F4 at 70mm and F5.6 at 200mm when examining the center of the frame. Additionally, there is a rapid gain in sharpness when initially stopping down from F2.8, and F4. Past F14, the lens shows the usual reduction in sharpness due to diffraction.
In conclusion, the lens is a great upgrade from any 70-200 F4 lens. The shallower depth of field and roughly 2/3 stop increase in light is well worth it, especially considering most first party 70-200mm F4 lenses are less sharp and more expensive. My only hesitation is the loud focusing, somewhat poor ergonomics, comparatively worse feel in the hand and hateful tripod mount. If any of these are of particular importance to you, spring for the first party 70-200mm F2.8 lenses. If these can't justify the significant gulf in price though, this is a great option. Either way, I don't think you can really go wrong.