I've had some spare time to dig into 4.0 now and I'm liking it a lot so far. The curve editor is niiiiiice and it really helps achieve some motion that was hard to pull off before, as well as give a birds eye view of how things are moving. Now that I've worked with it it's going to be one of those features that's tough to leave behind if I ever have to work in pre-4.0 files again!
Favour tool is also very slick, liking that a lot. The axis splits and +360 degree rotation are also absolutely lovely additions that will make keying things a lot more convenient.
Also have to say that I love the way that blog post is put together. Lovely animation work there.