Early feedback from testers already using Windows Vista RC1 (Release Candidate 1) report that the OS (operating system) is more stable than expected, which bodes well for Microsoft's plan to have Vista out according to its current schedule.

Microsoft has said since March it will release Windows Vista to business customers in November and to consumers in January 2007. Although many have suspected that the release will slip further, testers now say there's a good chance the company will meet its goal if the condition of RC1 is any indication.

"Overall I think Vista is looking very good at this point... I think all the worries of Vista slipping went out the window," said Brandon LeBlanc, a writer for LonghornBlogs, via email yesterday.

LeBlanc said Microsoft has made performance and stabilisation tweaks that testers requested after Beta 2.0, and the latest test version of the OS – which could be the final one before Vista is released to manufacturing – is solid enough for regular use.

"RC1 is quite usable for everyday work, as I am currently doing myself," he said.

LeBlanc said Vista is so far along in RC1, he does not think another release candidate will be required before final changes are made and the OS is sent off for manufacturing. The previous major client release of Windows, Windows XP, had two release candidates before it shipped to manufacturers.

To no one's surprise, however, there are still bugs to be ironed out before Vista will be ready for its final release.

LeBlanc said the OS needs some work in terms of its UI (user interface), for example. The test version "does lack some of the UI polish we were expecting at this point", he said. In Vista, Microsoft has completely revamped Windows' UI with a new 3D interface called Aero.

Another Vista tester, Andrew Brust, chief of new technology at New York consulting firm Twentysix New York, said the latest test release of Vista feels more "grown-up", even on hardware that is not necessarily optimised for the OS.

"Besides the fact that it's just a really nice OS, it feels very sprightly even on hardware that wasn't designed for it," he said.

Even smaller applications such as Solitaire and Minesweeper games have a next-generation look and feel in Windows Vista RC1, Brust said. "It's a trivial example, but it shows a certain attention to detail [on the part of Microsoft]," he said.

Harrison Hoffman, another Vista beta tester and one of the writers of the LiveSide blog, agreed that the latest test version of the OS could be used as a person's main desktop OS, even though it definitely needs some polish before final release.

"It might not be quite ready for prime time, but if you really wanted to, you could use this build as your primary OS, but be prepared for a few applications and devices to not work correctly," he said via email. "The OS does not hang, lag or crash as consistently as it used to. The performance has been greatly improved."

However, both LeBlanc and Hoffman noted that Windows Vista is still lacking driver support, a particularly sore subject because Vista has been billed as an OS in which devices will work as soon as you connect them without any further hassle, Hoffman said.

"The philosophy of Vista has been to have things 'just work' when you connect them and right now, some things just do not," he said. "Obviously this issue is going to get better with time and as hardware manufacturers work closer with Microsoft to remedy these problems."

LeBlanc sized up the hardware driver situation in Windows Vista RC1 this way: "Some work, some don't. Heck, Microsoft doesn't even have Vista drivers for some of its own hardware, including its new LifeCams."

Andrew Brust called driver compatibility Microsoft's "biggest impediment" to getting Vista out in time. "Driver compatibility will be key," he said.