Hi,
I use After Effects ALL the time, even for emailing and listening to music (joking)
I do like it alot, and version 7 has a lot to offer, but having used After Effects for so long, I feel like I have ran into a brick wall. Plus, I am very very interested in learning shake, been looking at a few classes on it. It is just the layout and workflow of AE is a bit long, in that, I find myself jumping between programs with it all the time, plus I do a lot of Chroma Key work, and Tracking work, both of which have been very time consuming in After Effects. I have had a go on other compositing titles, and in these, it is like, click and pop, out comes your green screen, or click, and it scene is steady again.
I dunno. try the trial After Effects and see for yourself, I don't honestly know much about Shake, as I have never used it, but I have watched as many free video tutorials as i could on the net, and have drooled over the way it works.
I hope this helps in some small way, but if you have any specific questions about AE, then please post back, and I will try and answer them for you.
Mel