Matmac,
Re :
1. In XMF, impositioning is done inside the xmf interface, in my opinion it works a bit like the dynastar impo.
1.1 I don't realy know what smartmarks are, but custom marks can always be put in your markslibrary.
2. also proofing is set up in the XMF flow, you can choose from a lot of standards. We are using a HP5500 just for prepressproofing, so just drafts. For us, this works just fine.
3. Coming from a trueflow workflow, it didn't take long to catch XMF, but I can imagine that, coming from preps and going to a ticketbased pdf workflow can take a little longer...
We're not having a lot of big issues on the client front, when you move along with the updates on the system you're working on (in my case Leopard), and the XMF updates, al should be fine.
CIP3 is coming along with your ticket, just define a connection to your press and it works, I'm using it towards a Ryobi 520 GX and it works fine.