"Vista is too bleeding-edge -- not for us, but for our clients," Krasowski said. PDSA's clients include large, blue-chip customers such as Kaiser Permanente and Boeing Inc. "They're all leery of Vista."

And why shouldn't they be? According to data released this spring by migration software vendor AppDNA, about a fifth of enterprise applications running on XP break when moved straight to Vista, mostly due to pre-XP-era code still lingering in the app. That increases to nearly half for apps migrated from 32-bit XP straight to 64-bit Vista.

Another reason is that Microsoft, in an attempt to catch up to the Mac, emphasized consumer-y aesthetic features with Vista, with WPF, Aero and the DirectX 10 3-D graphics rendering engine all aimed at making Vista or its apps more pleasing to the eye.

More attractive apps are more user-friendly apps, says Microsoft, and that translates into increased user productivity. But that message remains a hard sell to enterprises, who demand their apps stay "lean and mean," said Krasowski, not get "confused and cluttered."

Others say learning how to take advantage of Vista's new visual features remains daunting. Improving data presentation is "a good thing to do, but there is a lot of hacking through the undergrowth first," Bucknall said. "I don't think a lot of developers know how to get to that stage."

Noderer is optimistic. While XP-era technologies such as Windows Forms "will be around for many years to come," he said, Vista-era ones such as WPF "will slowly rise as the way to do Windows applications."

But others think that the rise in popularity of server-delivered business apps -- coupled with Microsoft's recent moves to make its Internet Explorer 8 browser behave more like other Web browsers -- could make Vista's client-side graphics-enhancing features irrelevant.

"98 per cent of the apps we write are for the Web," Krasowski said. "They're more flexible and easier to maintain. Many of our clients are migrating from apps written in VB6 or .Net."

Heather Havenstein contributed to this story.