This sounds like fantastic news. I've been using Impression since 1990 and wrote two books with Impression II, both of which I'm revising using Impression Publisher.
This means switching from my Iyonix back to the RPC, as I haven't bought Aemulor. The same applies to all my DTP/word processing as I haven't bought Ovation Pro either. I might not need either of them now.
I'd guess that Impression will have a bit of catching up to do, though.