Need a better lens, help?

[F1addict]

I have a Sony A300 with an 18-70mm kit lens and Sony 75-300mm f/4.5-5.6 lens . And while they both work pretty well, the 75-300 seems to get really soft past 200mm sometimes.
So I'm looking for something that would be a step up from this. This is the lens I currently have SAL-75300 | SAL-75300 - f/4.5-5.6 Telephoto Zoom Lens | Sony | SonyStyle USA

The few lens I've been thinking about are the Sony 70-300 f/4.5-5.6 G SAL-70300G | SAL-70300G 70-300mm f4.5-5.6 Telephoto Zoom | Sony | SonyStyle USA
The Tamron 70-200 f/2.8 Di LD Macro AF70-200mm F/2.8 Di LD (IF) Macro; Tamron USA, Inc. which is actually about $100 cheaper then the Sony but I've heard, that the autofocus isn't very fast, at least with Canon and Nikon, my camera has an inbody motor so I don't know if thats as much of a problem. I mostly shoot landscapes, car shows, and macro, but I do do some sports so the f/2.8 would be very helpful.
I've also hear that this old Minolta lens is supposed to be really good KEH Camera: Minolta Auto Focus - Zoom Lenses - 70-210 F4 MACRO (55) WITH HOOD, CAPS, 35MM SLR AUTO FOCUS ZOOM TELEPHOTO LENS That is the "beer can" lens right?

I'd like to keep it under $900. If it doesn't go to 300mm it isn't a big deal. I have no problem just cropping an image. With a 10mp camera the pictures are already far larger then I'd ever be printing.

Thanks for any help

 

[skieur]

One of the cameras I use is the Sony A350 with the 70 to 300mm Sony G lens. It provides surprisingly good colour and sharpness, even when shooting through haze, although I always use a polarizer.

skieur

 

[dxqcanada]

The Minolta beercan lens is very highly rated.

The Sony G lenses are high quality also ... but not cheap.