70-200mm f/4L OR 70-300mm f/4.0-5.6 IS

I'm looking for a zoom lense and both of these have popped up on my radar. Which (in your opinion) is better, the L or the IS? They are both around the same price.

Well, the advantage with the L is that you can use f/4 at the whole range where you can only have f/5.6 at 300mm for 70-300mm. Besides, the build quality will be different. The only advantage of 70-300mm will be its reach (300mm).

the IS too, how much would I missing without this at 200mm?

How often, where you plan to use this lens, do you get 1/320th shutter or faster @ f/4. If often, you don't need IS. if seldomly, you'll wish you had it.

the images from the L are just stunning

i would say go with the L ok it has no IS but lets say you normaly use iso 100 pop it up to 200 iso thats like giveing you one stop of IS i.e double your shutter speed thats the way i look at things .
Rob

Um. The disadvantage on the 70-300 is that you can only have f/4 at 70, not that you can only have f/5.6 at 300. You can set your aperture to f./5.6 at any focal length with either lens. I think what you meant to say was that you can't go any faster than f/5.6 at 300 (or anywhere much beyond 240 mm. You lose f/4 at around 120 mm as the maximum aperture becomes around f/4.5 indicated there, moviing to about f/5.1 or so at 180 - it actually gradually changes between f/4 and f/5.6, rather than taking abrupt steps as this implies). What you said sounds rather like you don't get f/5.6 at anything but 300.

If you shoot a lot in poor lighting conditions, you'll appreciate IS. If you can stay in the "safe zone" of above 1/250 with the 70-200, or above 1/500 with a lens in the 300 mm range, IS doesn't give you a lot of help. This, of course, assumes you aren't a caffiend.