Tamron 70-200mm 2.8 vs Tamron 70-300mm4-5.6 VC

Hi, i need help deciding on which of these lenses is right for me. I Do mostly nature and landscape photography and have been wanting to get a zoom lens. I've decided on either the 70-200mm or the 70-300mmVC based on reviews that have made them sound better than other makes.
The price difference is quite a lot the 70-200mm 2.8 is $750 and the 70-300mmVC 4-5.6 is $450

I assume the 70-300mmVC must have much worse image quality for having a farther range and also being $300 cheaper, but from the reviews i read this didn't seem to be true. Perhaps the reviews were just comparing this lens to other 70-300mm's.

Is the 70-300mmVC so much cheaper because of the 4-5.6 compared to the 70-200mm's 2.8? And how important is this when i do most of my shooting on a tripod right before sunset and right after sunset. I do care a lot about image quality, but i rarely make prints larger than 11' x 18'

Any advice would help, also any advice about other 70-200mm and 70-300mm lenses. I'm getting this lens to take with me on a roadtrip across the united states, and it will be my primary lens.

Basically they're apples and oranges. You would be well served to actually go visit a shop and handle all these lenses on your camera. The simple answer is the 70-200 2.8 is trying to be a pro caliber zoom, the 70-300 is consumer grade. Pro caliber, lot's of internal elements (glass), generally better grade construction, heavier fast lens speed. Consumer, fewer elements, lower build quality, lot's of plastic low speeds. Pro lenses are designed for low light or conditions where high shutter speeds are required. I own a Nikon 80-200, it's a beast and I would not recommend it as a walk around lens. It's a fantastic lens though.

If you want a good tele zoom for not much money I would suggest a Nikon AF-S VR 70-300mm f/4.5-5.6G IF ED, I would not bother with the Tamron, they maybe good, but it just not as good as the Nikon, invest in good glass and your keep that lens for a long time.

There is no way to compare the two lenses. The F2.8 is a good lens for indoor and arena and difficult lighting conditions (mainly of sports). The 70-300mm is a good all around general telephoto lens. Both lenses should give good photos.

If you planing to take photos at sports events purchase the 70-200 mm F2.8 other wise it really does not really mater.

i went with the 70-300mm i wont be doing any sport pictures and i'm more of an amateur