It didn't change my mind. I opened up Nexus 3 and did a side-by-side comparison with what I have in 3 that they are showing in 4 and decided it's most definitely not worth $99 for me.
The only consideration I had was to get the 10 expansion bundle, which would not only make each expansion much cheaper, but basically make the update 'free'. But given that it's still a hefty $349 commitment AND I can't choose the 10 expansions myself...I'd rather just put that money into another instrument *cough* Avenger *cough*