zombie's question is the right one - "Why are you changing it?"...................Maybe if you laid out your pain-points folks could give more pertinent opinions.
Exactly. What's broken with TrueFlow? Being able to know that will permit others to give more useful input.
My background is Apogee, Prinect, Prinect, Creo, Prinect, Prinect, Prinect.
I've evaluated Fuji XMF, Agfa Apogee, Heidelberg Prinect, Kodak Prinergy, Screen TrueFlow and Esko. Each system has strengths and weaknesses.
Prinect can be an awesome product when properly utilized and configured. It can be a horrible headache if you refuse to conform to the way it works or just refuse to learn how to use it to its potential (I've seen all three scenarios first hand). It's been a while since I've imposed a book (I left commercial printing for packaging) but Heidelberg SignaStation was(still is?) hands-down the best imposition program out there for commercial work like you described. If you are utilizing modern Heidelberg presses, folders, cutters, stitcher/binders it will integrate and talk directly to the equipment (reduced makeready/setup, quality-control, etc.). This integration seems to be the focus of Heidelberg Prinect R&D much to the detriment of some common and desperately needed prepress/preflight functionality.
Prinergy is an awesome product with a huge footprint in the industry. I worry what will happen to it with Kodak being in such dire financial condition. A huge software platform requires massive R&D dollars. I suppose the same thing could be said about Heidelberg though.
I haven't seen Apogee in a few generations. It's been around for a long time and has a very loyal user base. Beyond that I don't have much input.
I'd suggest taking a look at Fuji XMF, RAMPAGE and Esko as well so that you have a clear understanding of what is out there and what your options are. It's never a good idea to write other options off without investigation.