It's been a long time since I've used the Acid software, but I don't recall it being aimed at impromptu or live performance. Whereas Live is ... well Live. Wireup all sorts of stuff, forget arrangement view completely (or maybe, leave it running on record), and then just jam out.
I don't agree - while Live was one of the first mature tools for performing, don't be fooled by the name. Studio work, production and arrangement view aren't second class citizens at all in my opinion. I switched from Logic to Live and spend most of my time in arrangement view. The session view is just a bonus for quick sketching for me.
