[dgaies]

Both Tamrons sound the same and have similar AF speeds. Can't go wrong with either, really. All depends on your preferred focal range.

Yeah, the 17-50 and 28-75 are pretty much the same lens, just with a shifted focal length range. It all comes down to whether you want the 17-28mm range or the 50-70mm range in addition to the 28-50mm range that they have in common.

The focus speed of either lenses is decent, plenty fast for shooting people at a wedding (although I've never shot a wedding with one, it's my go to people shooting lenses and the AF speed has always been a non-issue. As for sound, the turning of the AF motor is certainly audible, but nothing too distracting nor anything that should case an issue or concern (IMO).