Imposition really shouldn't be done within InDesign. InDesign is a layout program.
For most modern print workflows, imposition is done on the PDF workflow system, the RIP, or in many cases for digitial printers, the DFE (digital front end of the device). Othewise, another much better choice than doing imposition in InDesign is to export PDF in logical page order and perform the imposition in Acrobat Pro using one or another of various commercially-available plug-ins available for this purpose.
One set of such plug-ins is Quite Imposing and Quite Imposing Plus from Quite Software (http://www.quite.com/).
Are you trying to impose internally to ID, or externally? How complex are the impositions you need?
IDImposer isn't the most intuitive software I've used, but it can handle quite a few types of impostion inside ID. Overview | IDImposer
We are trying to do it internally but after reading a couple of responses we are going to try out acrobat. Thank you for taking the time to respond.
Thank you. We are going to look into Acrobat.