I am debating whether to get either the

Canon EF 24-105mm f4 L IS lens
or
Canon EF 24-70mm f2.8 L lens.

I currently have a Canon 17-40mm f4 lens that I do love. However, I hate that I can't zoom in more.

I was going to get the 24-105mm lens. I also love that it's has Image Stabilization. However, I am a little leary since it's only an f4.... where the 24-70mm is a 2.8... but doesn't zoom as much. (Both lenses cost about the same. So price isn't a factor). Too bad the 24-105mm doesn't come in a 2.8, or that would make my decision

Or is there possibly another mid-range zoom lens that is better than the 2 I am debating between?

Help me! (and thank you in advance )

24-70 with 2.8. The most sensitive AF sensors in your Canon body activate at f2.8 and faster. I agree, a 24-105F2.8 would be awesome!

I just tried them both out last weekend. I really wanted to love the 24-105, but the viewfinder is noticeably dimmer from it being a f/4

the 24-70 is faster, sharper, has better background blur etc, but its also considerably heavier and longer.

Either is an excellent choice, but I'll be going with the 24-70 soon, I just don't care for the mid range much so its not a priority.

Many hoped for a 24-70 IS, but it didn't happen.

24-70 no doubt

It's heavy for sure though

I have both. I use the 24-105 for any formal shots with flash but it is great outside with available light too. It is my main lens in the studio as well. It is way too flexible in these situations.

The 24-70 is helpful in low light but I tend to use other lenses in extremely low light. This lens was the lens for me until I went full frame. After that, I wanted more focal length for close up and 3/4 length shots.

Overall with a 20D or 300D I would say the 24-70. With a full frame, I am not so sure for the way I shoot.

This may not answer your question......just my observations.

24-70, but buy locally. These are notorious for model to model inconsistancies. You want to make sure you get a good copy. Also, there are a few things you should be aware of. The first is that the 24-70 quite often doesn't play nice with 1.6 crop (look for back-focus), and you must always remember to zoom, then focus. This is because it is a variable focus zoom. This means that if you focus, then zoom, it will be out of focus. By a LOT. It is an awesome piece of equipment, however.
Cory

I love my 24-70mm on my 5D. You'll definitely want the 2.8!

i vote for the 24-70

Just unpacked my 240-70 a few weeks ago, so you can tell which my choice was. Loving it. Best portrait lens I've ever owned, in terms of versatility married with image quality.

I own both an i have to say they are equally sharp. I use the 24-70 for indoors, and the 24-105 is for my walk around lens. I would not get rid of either of them. You need to consider what you will be shooting.

24-70 2.8 is the best
I love mine

thank you everyone for your feedback! I guess it's a landslide vote, eh? THANKS

I haven't shot with the 24-70 but I have the 24-105 IS and I LOVE that lens. I think I can make up for the speed by having the IS. It's extremely sharp and I can hand hold REALLY slow shutter speeds. I mean, 2.8 is great for many things, but so is the IS.

Call me the odd lady out; but I have rented both and LOVE the 24-105L IS
WOW that baby rocks. But I shoot on location, mainly outdoors. I was worried about the f4 but as soon as I had it in my hands, no worries. I have my primes that I love too if I need them.
So hopefully I can get a great deal on one at WPPI