Over the past couple of months, I have had in-depth conversations with five CIOs that have made a significant commitment to Windows Vista.

One of the main issues I explored with each of them was the foundation upon which the business case for migration was made. The responses I received were remarkably consistent, and not completely in tune with the way Microsoft articulates the Vista proposition.

What all these guys said was that their business case for Vista, i.e. the one put before the board, CFO and/or other significant stakeholders, was founded on benefits in two key areas - security risk management and operational cost control.

From a security perspective, the focus tended to be on three specific attributes of Vista - better run-time security in the operating system itself, more effective policy enforcement, and the ability to encrypt data on notebook PCs through BitLocker.

What I found interesting was the view that while all three of these security related benefits were considered to be significant, it was the last one in particular that was most frequently highlighted as resonating directly with business stakeholders. Recent high profile press coverage about notebooks storing sensitive data being lost or stolen was seen to have an influence here in terms of awareness. Against this background, Vista's ability to deal with an acknowledged business risk straight out-of-the-box was perceived to be of significant value.

Beyond security, double-digit reductions in operational cost generally formed the substance of the business case in financial terms. The general streamlining of the management and maintenance process was highlighted as part of this, and the dramatic simplification of image management in particular was seen as a significant contributor to the savings in the large multi-national environment.

Something I was personally very sceptical about, but which three of the five CIOs defended very strongly, were the savings in relation to desktop power consumption. Numbers from 50 Euros per year per desktop upwards were cited as savings, though to be absolutely clear, the benefit comes from better centralised control and enforcement of power management policies rather than efficiencies in the way Vista uses hardware resources.

When asked about the element that was clearly missing from these business cases, namely improved user productivity, the general consensus was that this was a red herring. The most positive view was that there is likely to be some impact in this area, but it is impossible to measure in any tangible way, so why would you dilute an otherwise solid business case with something that could easily discredit it? Best to stick the list of intangibles in your bottom drawer and run with what you can defend with confidence.

And it is on this point that the CIOs I have been speaking with diverge from the view articulated by Microsoft. In fact one said the obsessive reference to the great user interface, user facing productivity features, etc caused a lot of distraction and confusion when he invited a Microsoft executive to meet some of his business sponsors. When a stakeholder says, "I don't understand, I thought we were doing this to save money", it doesn't actually help to get the investment case signed off.

There are a couple of lessons that fall out of this. Firstly, if you are going through the process of evaluating the business case for Vista yourself, the abovementioned criteria will hopefully provide some thoughts based on where at least a few others have put the emphasis - particularly in a large corporate or public sector environment.

Secondly, the feedback suggests that you should be prepared for business sponsors to get confused about the rationale for migrating based on the messages broadcast by Microsoft both directly and indirectly through advertising, the media, marketing collateral, etc. The trick here is agreeing that it will be a great spin-off benefit if all of the claimed or suspected end user productivity gains are realised, but keep the investment case itself focused on the more solid stuff that can be defended under cross-examination.

Finally, there is a message in here for any Microsoft executives reading this. If you can curb your enthusiasm for obsessing about the Wow! and focus on the things that drive decisions, you might see more movement in the market.