100-400 f4.5-5.6L IS USM vs 70-200mm f/2.8L IS USM

My wife and I are celebrating our 1st anniversary next weekend and I found out she spent a lot of money on my gift. I was worried about what it could be so I did some investigating and found out she got me the 100-400 f4.5-5.6L IS USM lens (presumably to replace my 70-300 lens).

I was wondering if perhaps the 70-200 lens may be more right for me. I don't think she would mind if I exchanged it because the prices are similar. I would like to ask what are the main uses of the 70-200 lens versus the 100-400 lens.

I don't typically shoot at long focal lengths too often and tend to use my 17-55 lens 90% of the time. When I have used my 70-300 lens it is typically to take photos of my dogs running around or for candid photos while on vacation.

The 70-200 lens looks like it may be better for portraits which I am trying to do a little more of and has a wider aperture which I like. The 100-400 seems to only have the longer focal length going for it versus the 70-200. I could have used it last year while on safari in Tanzania, but don't otherwise do a lot of wildlife photography (besides my dogs). What do people think of these two lenses and what does each lens excel at? Thanks.

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